Create 492.cpp

492.cpp

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+// C++ program for Knight Tour problem
+#include <bits/stdc++.h>
+using namespace std;
+
+#define N 8
+
+int solveKTUtil(int x, int y, int movei, int sol[N][N],
+				int xMove[], int yMove[]);
+
+/* A utility function to check if i,j are
+valid indexes for N*N chessboard */
+int isSafe(int x, int y, int sol[N][N])
+{
+	return (x >= 0 && x < N && y >= 0 && y < N
+			&& sol[x][y] == -1);
+}
+
+/* A utility function to print
+solution matrix sol[N][N] */
+void printSolution(int sol[N][N])
+{
+	for (int x = 0; x < N; x++) {
+		for (int y = 0; y < N; y++)
+			cout << " " << setw(2) << sol[x][y] << " ";
+		cout << endl;
+	}
+}
+
+/* This function solves the Knight Tour problem using
+Backtracking. This function mainly uses solveKTUtil()
+to solve the problem. It returns false if no complete
+tour is possible, otherwise return true and prints the
+tour.
+Please note that there may be more than one solutions,
+this function prints one of the feasible solutions. */
+int solveKT()
+{
+	int sol[N][N];
+
+	/* Initialization of solution matrix */
+	for (int x = 0; x < N; x++)
+		for (int y = 0; y < N; y++)
+			sol[x][y] = -1;
+
+	/* xMove[] and yMove[] define next move of Knight.
+	xMove[] is for next value of x coordinate
+	yMove[] is for next value of y coordinate */
+	int xMove[8] = { 2, 1, -1, -2, -2, -1, 1, 2 };
+	int yMove[8] = { 1, 2, 2, 1, -1, -2, -2, -1 };
+
+	// Since the Knight is initially at the first block
+	sol[0][0] = 0;
+
+	/* Start from 0,0 and explore all tours using
+	solveKTUtil() */
+	if (solveKTUtil(0, 0, 1, sol, xMove, yMove) == 0) {
+		cout << "Solution does not exist";
+		return 0;
+	}
+	else
+		printSolution(sol);
+
+	return 1;
+}
+
+/* A recursive utility function to solve Knight Tour
+problem */
+int solveKTUtil(int x, int y, int movei, int sol[N][N],
+				int xMove[N], int yMove[N])
+{
+	int k, next_x, next_y;
+	if (movei == N * N)
+		return 1;
+
+	/* Try all next moves from
+	the current coordinate x, y */
+	for (k = 0; k < 8; k++) {
+		next_x = x + xMove[k];
+		next_y = y + yMove[k];
+		if (isSafe(next_x, next_y, sol)) {
+			sol[next_x][next_y] = movei;
+			if (solveKTUtil(next_x, next_y, movei + 1, sol,
+							xMove, yMove)
+				== 1)
+				return 1;
+			else
+
+			// backtracking
+				sol[next_x][next_y] = -1;
+		}
+	}
+	return 0;
+}
+
+// Driver Code
+int main()
+{
+	// Function Call
+	solveKT();
+	return 0;
+}
+
+