-
Notifications
You must be signed in to change notification settings - Fork 11
/
Day-064.cpp
60 lines (52 loc) · 1.46 KB
/
Day-064.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
/*
This problem was asked by Google.
A knight's tour is a sequence of moves by a knight on a chessboard such that all squares are visited once.
Given N, write a function to return the number of knight's tours on an N by N chessboard.
My Testcase :
input : 1 , Output : 1
input : 2 , Output : 0
input : 3 , Output : 0
input : 4 , Output : 0
input : 5 , Output : 1728 (it took 23 seconds)
*/
#include <bits/stdc++.h>
using namespace std;
vector<pair<int,int>>jump{{2,1},{2,-1},{-2,1},{-2,-1},{1,2},{-1,2},{1,-2},{-1,-2}};
vector<vector<bool>>grid;
bool valid(int x , int y , int n){
if(x>n || y>n || x<1 || y<1){
return false;
}
if(grid[x][y] == true )
return false;
return true;
}
long long count_ways(int x , int y , int n ,int move_number = 1){
if(move_number == n*n){
return 1;
}
int ways_counter{};
if(x>n || y>n || x<1 || y<1){
return ways_counter;
}
grid[x][y] = true;
for(int k=0;k<(int)jump.size();++k){
if(valid(x+jump.at(k).first , y+jump.at(k).second , n)){
ways_counter+=count_ways(x+jump.at(k).first , y+jump.at(k).second , n , move_number+1 );
}
}
grid[x][y] = false;
return ways_counter;
}
int main(void){
int n; cin>>n;
grid.assign(n+1 , vector<bool>(n+1,false));
long long counter{};
for(int i=1;i<=n;++i){
for(int j=1;j<=n;++j){
counter+=count_ways(i,j,n);
}
}
cout<<counter<<'\n';
return 0;
}