Update and rename knight-tour.cpp to knight_tour.cpp

Add information about the file for brief intro

Backtracking/knight_tour.cpp

@@ -0,0 +1,68 @@
+#include<bits/stdc++.h>
+# define n 8
+
+/**
+A knight's tour is a sequence of moves of a knight on a chessboard
+such that the knight visits every square only once. If the knight 
+ends on a square that is one knight's move from the beginning 
+square (so that it could tour the board again immediately, following 
+the same path), the tour is closed; otherwise, it is open.
+**/
+
+using namespace std;
+bool issafe(int x,int y,int sol[n][n])
+{
+    return (x<n && x>=0 && y<n && y>=0 && sol[x][y]==-1);
+
+}
+bool solve(int x,int y, int mov, int sol[n][n], int xmov[n], int ymov[n])
+{
+    int k,xnext,ynext;
+
+    if(mov == n*n)
+        return true;
+
+    for(k=0;k<8;k++)
+    {
+        xnext=x+xmov[k];
+        ynext=y+ymov[k];
+
+        if(issafe(xnext,ynext,sol))
+            {
+                sol[xnext][ynext]=mov;
+
+                if(solve(xnext,ynext,mov+1,sol,xmov,ymov)==true)
+                    return true;
+                else
+                    sol[xnext][ynext]=-1;
+            }
+    }
+    return false;
+}
+int main()
+{
+    //initialize();
+
+    int sol[n][n];
+    int i,j;
+    for(i=0;i<n;i++)
+        for(j=0;j<n;j++)
+            sol[i][j]=-1;
+
+    int xmov[8] = {  2, 1, -1, -2, -2, -1,  1,  2 };
+    int ymov[8] = {  1, 2,  2,  1, -1, -2, -2, -1 };
+    sol[0][0]=0;
+
+    bool flag=solve(0,0,1,sol,xmov,ymov);
+    if(flag==false)
+        cout<<"solution doesnot exist \n";
+    else
+    {
+        for(i=0;i<n;i++)
+        {
+            for(j=0;j<n;j++)
+                cout<<sol[i][j]<<"  ";
+            cout<<"\n";
+        }
+    }
+}