add hw6 solution
This commit is contained in:
JamesFlare1212
337
hws/inverse_word_search/main.cpp
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337
hws/inverse_word_search/main.cpp
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#include <iostream>
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#include <fstream>
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#include <sstream>
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#include <vector>
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#include <string>
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#include <set>
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#include <algorithm>
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#include <cstdlib>
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#include <cctype>
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#include <climits>
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#include <utility>
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using namespace std;
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struct Placement {
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int r, c; // starting row and column
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int dr, dc; // direction increments
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string word; // the required word to place
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};
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// Check if the given string s contains any forbidden word or its reverse.
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bool containsForbidden(const string &s, const vector<string> &forbWords) {
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for (size_t i = 0; i < forbWords.size(); i++) {
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if (s.find(forbWords[i]) != string::npos)
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return true;
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string rev = forbWords[i];
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reverse(rev.begin(), rev.end());
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if (s.find(rev) != string::npos)
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return true;
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}
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return false;
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}
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// Checks the full board for forbidden words in every contiguous line.
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bool fullForbiddenCheck(const vector< vector<char> > &board, const vector<string> &forbWords) {
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int H = board.size();
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if (H == 0) return false;
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int W = board[0].size();
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int dirs[8][2] = { {0,1}, {0,-1}, {1,0}, {-1,0}, {1,1}, {1,-1}, {-1,1}, {-1,-1} };
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for (int r = 0; r < H; r++) {
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for (int c = 0; c < W; c++) {
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for (int d = 0; d < 8; d++) {
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int dr = dirs[d][0], dc = dirs[d][1];
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string line = "";
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int rr = r, cc = c;
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while (rr >= 0 && rr < H && cc >= 0 && cc < W) {
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line.push_back(board[rr][cc]);
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if (containsForbidden(line, forbWords))
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return true;
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rr += dr;
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cc += dc;
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}
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}
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}
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}
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return false;
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}
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// Convert the board into a single string (rows separated by newline).
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string boardToString(const vector< vector<char> > &board) {
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string s = "";
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for (size_t i = 0; i < board.size(); i++) {
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for (size_t j = 0; j < board[i].size(); j++) {
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s.push_back(board[i][j]);
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}
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if (i < board.size()-1)
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s.push_back('\n');
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}
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return s;
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}
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// Given a newly assigned cell (r,c), check in all eight directions the contiguous block
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bool checkCellDirections(int r, int c, const vector< vector<char> > &board, const vector<string> &forbWords, int minForbidLen) {
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int H = board.size(), W = board[0].size();
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int dirs[8][2] = { {0,1}, {0,-1}, {1,0}, {-1,0}, {1,1}, {1,-1}, {-1,1}, {-1,-1} };
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for (int d = 0; d < 8; d++) {
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int dr = dirs[d][0], dc = dirs[d][1];
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int sr = r, sc = c;
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// Go backwards from (r,c)
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while (true) {
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int pr = sr - dr, pc = sc - dc;
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if (pr < 0 || pr >= H || pc < 0 || pc >= W) break;
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if (board[pr][pc] == '?') break;
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sr = pr; sc = pc;
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}
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// Build the contiguous block from (sr,sc)
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string block = "";
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int cr = sr, cc = sc;
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while (cr >= 0 && cr < H && cc >= 0 && cc < W) {
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if (board[cr][cc] == '?') break;
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block.push_back(board[cr][cc]);
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cr += dr; cc += dc;
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}
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if ((int)block.size() >= minForbidLen) {
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if (containsForbidden(block, forbWords))
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return false;
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}
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}
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return true;
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}
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// Recursive function to fill free positions with letters
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bool fillFreePositions(vector<vector<char>> &board,
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vector<pair<int,int>> &freePositions,
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int index,
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const vector<string> &forbWords,
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int minForbidLen,
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set<string> &solutionSet,
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vector<string> &solutions,
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bool findOne,
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const string &outputFile) {
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// Base case: all free positions filled
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if (index == freePositions.size()) {
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// Check if the solution is valid
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if (!fullForbiddenCheck(board, forbWords)) {
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string solStr = boardToString(board);
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if (solutionSet.find(solStr) == solutionSet.end()) {
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solutionSet.insert(solStr);
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solutions.push_back(solStr);
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// If we need just one solution, write it to file and exit
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if (findOne) {
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ofstream fout(outputFile.c_str());
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fout << "Board:" << endl;
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istringstream iss(solStr);
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string line;
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while(getline(iss, line))
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fout << " " << line << endl;
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fout.close();
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return true;
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}
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}
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}
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return false; // Continue searching for more solutions
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}
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// Try each letter for the current free position
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int r = freePositions[index].first;
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int c = freePositions[index].second;
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for (char ch = 'a'; ch <= 'z'; ch++) {
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board[r][c] = ch;
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// Check if the new letter creates any forbidden words
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if (checkCellDirections(r, c, board, forbWords, minForbidLen)) {
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// Recursively fill the next position
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if (fillFreePositions(board, freePositions, index + 1, forbWords, minForbidLen,
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solutionSet, solutions, findOne, outputFile)) {
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return true; // Solution found and we only need one
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}
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}
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}
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// Backtrack: Reset the cell
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board[r][c] = '?';
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return false;
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}
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// Recursive function to place required words
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bool placeRequiredWords(vector<vector<char>> &board,
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const vector<vector<Placement>> &placements,
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int wordIndex,
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const vector<string> &forbWords,
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int minForbidLen,
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set<string> &solutionSet,
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vector<string> &solutions,
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bool findOne,
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const string &outputFile) {
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// Base case: all required words placed
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if (wordIndex == placements.size()) {
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// Find free positions (cells marked with '?')
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vector<pair<int,int>> freePositions;
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for (int i = 0; i < board.size(); i++) {
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for (int j = 0; j < board[0].size(); j++) {
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if (board[i][j] == '?') {
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freePositions.push_back(make_pair(i, j));
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}
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}
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}
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// Recursively fill free positions
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return fillFreePositions(board, freePositions, 0, forbWords, minForbidLen,
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solutionSet, solutions, findOne, outputFile);
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}
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// Try each placement for the current word
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for (const Placement &p : placements[wordIndex]) {
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// Create a temporary copy of the board
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vector<vector<char>> boardCopy = board;
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bool conflict = false;
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// Try to place the word
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for (size_t k = 0; k < p.word.size(); k++) {
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int r = p.r + p.dr * k;
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int c = p.c + p.dc * k;
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if (boardCopy[r][c] == '?' || boardCopy[r][c] == p.word[k]) {
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boardCopy[r][c] = p.word[k];
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} else {
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conflict = true;
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break;
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}
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}
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// If no conflict and no forbidden words formed, continue to the next word
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if (!conflict && !fullForbiddenCheck(boardCopy, forbWords)) {
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if (placeRequiredWords(boardCopy, placements, wordIndex + 1, forbWords, minForbidLen,
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solutionSet, solutions, findOne, outputFile)) {
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return true; // Solution found and we only need one
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}
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}
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}
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return false; // No solution found with any placement for this word
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}
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int main(int argc, char* argv[]) {
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if (argc != 4) {
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cout << "Usage: " << argv[0] << " input.txt output.txt one_solution|all_solutions" << endl;
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return 1;
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}
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string inputFile = argv[1];
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string outputFile = argv[2];
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string mode = argv[3];
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bool findOne = false;
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if (mode == "one_solution") {
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findOne = true;
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} else if (mode == "all_solutions") {
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findOne = false;
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} else {
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cout << "Invalid mode. Use one_solution or all_solutions." << endl;
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return 1;
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}
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ifstream fin(inputFile.c_str());
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if (!fin) {
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cout << "Cannot open input file." << endl;
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return 1;
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}
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int width, height;
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fin >> width >> height;
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string dummy;
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getline(fin, dummy); // consume rest of first line
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// Separate required and forbidden words.
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vector<string> reqWords;
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vector<string> forbWords;
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while(getline(fin, dummy)) {
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if(dummy.size() == 0)
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continue;
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char sign = dummy[0];
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string word = "";
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int pos = 1;
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while (pos < dummy.size() && isspace(dummy[pos])) pos++;
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while (pos < dummy.size() && !isspace(dummy[pos])) {
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word.push_back(dummy[pos]);
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pos++;
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}
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if (sign == '+')
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reqWords.push_back(word);
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else if (sign == '-')
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forbWords.push_back(word);
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}
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fin.close();
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// Precompute minimum forbidden word length.
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int minForbidLen = INT_MAX;
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for (size_t i = 0; i < forbWords.size(); i++) {
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if ((int)forbWords[i].size() < minForbidLen)
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minForbidLen = forbWords[i].size();
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}
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if (forbWords.empty())
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minForbidLen = 27; // no forbidden word; no check needed
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// Precompute all placements for each required word.
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vector<vector<Placement>> placements;
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placements.resize(reqWords.size());
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int directions[8][2] = { {0,1}, {0,-1}, {1,0}, {-1,0}, {1,1}, {1,-1}, {-1,1}, {-1,-1} };
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for (size_t w = 0; w < reqWords.size(); w++) {
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string word = reqWords[w];
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for (int r = 0; r < height; r++) {
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for (int c = 0; c < width; c++) {
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for (int d = 0; d < 8; d++) {
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int dr = directions[d][0], dc = directions[d][1];
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int end_r = r + dr * (word.size() - 1);
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int end_c = c + dc * (word.size() - 1);
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if (end_r < 0 || end_r >= height || end_c < 0 || end_c >= width)
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continue;
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Placement p;
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p.r = r; p.c = c; p.dr = dr; p.dc = dc; p.word = word;
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placements[w].push_back(p);
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}
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}
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}
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if (placements[w].empty()) {
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ofstream fout(outputFile.c_str());
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fout << "No solutions found" << endl;
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fout.close();
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return 0;
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}
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}
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// Use a set to avoid duplicate solutions.
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set<string> solutionSet;
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vector<string> solutions;
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// Prepare the base board filled with '?'.
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vector<vector<char>> board(height, vector<char>(width, '?'));
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// Call the recursive function to place required words
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placeRequiredWords(board, placements, 0, forbWords, minForbidLen,
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solutionSet, solutions, findOne, outputFile);
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// Write out all found solutions (if findOne is true, we've already written the solution).
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if (!findOne || solutions.empty()) {
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ofstream fout(outputFile.c_str());
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if (solutions.empty()) {
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fout << "No solutions found" << endl;
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} else {
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fout << solutions.size() << " solution(s)" << endl;
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for (size_t s = 0; s < solutions.size(); s++) {
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fout << "Board:" << endl;
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istringstream iss(solutions[s]);
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string line;
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while(getline(iss, line))
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fout << " " << line << endl;
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}
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}
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fout.close();
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}
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return 0;
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}
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