Create n-queen.cpp

n-queen.cpp

@@ -0,0 +1,66 @@
+class Solution {
+public:
+    vector<vector<string>> ans;
+    bool issafe(int board[][10], int i, int j, int n) {
+	for (int row = 0; row < i; ++row) {
+		if (board[row][j] == 1) {
+			return false;
+		}
+	}
+	int x = i;
+	int y = j;
+	while (x >= 0 && y >= 0) {
+		if (board[x][y]) {
+			return false;
+		}
+		x--;
+		y--;
+	}
+	x = i;
+	y = j;
+	while (x >= 0 && y < n) {
+		if (board[x][y] == 1) {
+			return false;
+		}
+		x--;
+		y++;
+	}
+	return true;
+}
+
+bool solveNqueen(int board[][10], int i, int n) {
+	if (i == n) {
+        vector<string> temp;
+		for (int i = 0; i < n; ++i) {
+            string s;
+			for (int j = 0; j < n; ++j) {
+				if (board[i][j] == 1) {
+                    s.push_back('Q');
+				}
+                else {
+                    s.push_back('.');
+                }
+            }
+            temp.push_back(s);
+		}
+        ans.push_back(temp);
+		return false;
+	}
+	for (int j = 0; j < n; ++j) {
+		if (issafe(board, i, j, n)) {
+			board[i][j] = 1;
+			bool nextqueenrakhpaye = solveNqueen(board, i + 1, n);
+			if (nextqueenrakhpaye) {
+				return true;
+			}
+			board[i][j] = 0;
+		}
+	}
+	return false;
+}
+    vector<vector<string>> solveNQueens(int n) {
+        int board[10][10] = {};
+        solveNqueen(board, 0, n);
+        return ans;
+    }
+};