Create main.cpp

Author: JawadSher

22 - Backtracking Algorithm Based Problems/03 - Sudoku Solver/main.cpp

@@ -0,0 +1,39 @@
+class Solution {
+public:
+    bool isSafe(int row, int col, vector<vector<char>>& board, int value){
+        char ch = value + '0';
+
+        for(int i = 0; i < board[0].size(); i++){
+            if(board[row][i] == ch) return false;
+            if(board[i][col] == ch) return false;
+            if(board[3*(row/3) + i/3][3*(col/3) + i%3] == ch) return false;
+        }
+        return true;
+    }
+    bool solve(vector<vector<char>>& board){
+        int n = board[0].size();
+
+        for(int row = 0; row < n; row++){
+            for(int col = 0; col < n; col++){
+                if(board[row][col] == '.'){
+                    for(int val = 1; val <= 9; val++){
+                        if(isSafe(row, col, board, val)){
+                            char ch = val + '0';
+                            board[row][col] = ch;
+                            if(solve(board)) return true;
+                            board[row][col] = '.';
+                        }
+
+                    }
+
+                    return false;
+                }
+            }
+        }
+
+        return true;
+    }
+    void solveSudoku(vector<vector<char>>& board) {
+        solve(board);
+    }
+};