Added folder Backtracking problems and added a simple problem in it

Backtracking problems/CountPositions.cpp

@@ -0,0 +1,50 @@
+//You are given a 10*10 chess board and a current position of knight(i, j).
+//You have to find maximum number of blocks where knight can be in exactly N moves.
+//1<=i,j<=10.
+
+#include<bits/stdc++.h>
+using namespace std;
+#define fast ios_base::sync_with_stdio(false)
+#define fast_input cin.tie(NULL)
+#define fast_output cout.tie(NULL)
+
+int v[10][10] = {0};
+
+void solve(int x , int y , int v[10][10] , int curr , int n)
+{
+    if(x<0 || y<0 || x>=10 || y>=10 || curr > n)
+      return ;
+    if(curr == n)
+      v[x][y] = 1;
+    solve(x+2,y+1,v , curr+1 , n);
+    solve(x+1,y+2,v , curr+1 , n);
+    solve(x-2,y+1,v , curr+1 , n);
+    solve(x-1,y+2,v , curr+1 , n);
+    solve(x+2,y-1,v , curr+1 , n);
+    solve(x+1,y-2,v , curr+1 , n);
+    solve(x-2,y-1,v , curr+1 , n);
+    solve(x-1,y-2,v , curr+1 , n);
+}
+int main()
+{
+  fast;
+  fast_input;
+  fast_output;
+  int i,j,n;
+  cin>>i>>j>>n;
+  solve(i-1, j-1, v , 0 , n);
+  int count = 0;
+  for(int i=0; i<10 ; i++){
+    for(int j=0; j<10 ; j++){
+      if(v[i][j] == 1)
+        count++;
+    }
+  }
+  cout<<count<<"\n";
+  for(int i =0 ; i<10 ; i++){
+    for(int j=0 ; j<10 ; j++){
+      v[i][j] = 0;
+    }
+  }
+  return 0;
+}