Created N_Queens.c

C/N_Queens.c

@@ -0,0 +1,77 @@
+#define N 4
+#include <stdbool.h>
+#include <stdio.h>
+
+void printSolution(int board[N][N])
+{
+	for (int i = 0; i < N; i++) {
+		for (int j = 0; j < N; j++)
+			printf(" %d ", board[i][j]);
+		printf("\n");
+	}
+}
+
+
+bool isSafe(int board[N][N], int row, int col)
+{
+	int i, j;
+
+	for (i = 0; i < col; i++)
+		if (board[row][i])
+			return false;
+
+	for (i = row, j = col; i >= 0 && j >= 0; i--, j--)
+		if (board[i][j])
+			return false;
+
+	for (i = row, j = col; j >= 0 && i < N; i++, j--)
+		if (board[i][j])
+			return false;
+
+	return true;
+}
+
+bool solveNQUtil(int board[N][N], int col)
+{
+
+	if (col >= N)
+		return true;
+
+	for (int i = 0; i < N; i++) {
+
+		if (isSafe(board, i, col)) {
+			board[i][col] = 1;
+
+			if (solveNQUtil(board, col + 1))
+				return true;
+
+			board[i][col] = 0; // BACKTRACK
+		}
+	}
+
+	return false;
+}
+
+
+bool solveNQ()
+{
+	int board[N][N] = { { 0, 0, 0, 0 },
+						{ 0, 0, 0, 0 },
+						{ 0, 0, 0, 0 },
+						{ 0, 0, 0, 0 } };
+
+	if (solveNQUtil(board, 0) == false) {
+		printf("Solution does not exist");
+		return false;
+	}
+
+	printSolution(board);
+	return true;
+}
+
+int main()
+{
+	solveNQ();
+	return 0;
+}
+