📦 ved015 / Codeforces-solution

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74#include<bits/stdc++.h>
#include<iostream>
#include<vector>
#include<algorithm>
#include<map>
#include<set>
#include<string>
using namespace std;

typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<string> vs;
typedef vector<long long> vll;
typedef vector<vector<ll> > vvll;

#define fastio() ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define pb push_back
#define mp make_pair
#define sz(x) ((int)(x).size())
#define all(x) x.begin(),x.end()

ll max(ll a, ll b, ll c){ return max(a, max(b, c));}
ll min(ll a, ll b, ll c){ return min(a, min(b, c));}
ll gcd(ll a, ll b) {if (b > a) {return gcd(b, a);} if (b == 0) {return a;} return gcd(b, a % b);}
ll fact(ll a) { return (a <= 1) ? 1 : a * fact(a - 1); }

vll factors(int n) { vll ans; int l = sqrt(n); for (int i = 1; i <= l; i++) { if (n % i == 0){ if (n/i == i) ans.pb(i); else {ans.pb(i); ans.pb(n/i);}}} return ans;}
string DecimalToBinary(ll num){string str; while(num){if(num & 1) str.pb('1');else str.pb('0');num>>=1;}return str;}
ll BinaryToDecimal(string num){ll ans = 0; ll base = 1; for (int i = sz(num) - 1; i >= 0; i--) {if (num[i] == '1') ans += base; base<<=1;}return ans;}

int n = 8;
int result = 0;

void solve(int row, vector<string> &board, vector<bool> &cols, vector<bool> &diag1, vector<bool> &diag2) {
    if (row == n) {
        result++;
        return;
    }
    
    for (int col = 0; col < n; col++) {
        if (board[row][col] == '*' || cols[col] || diag1[row + col] || diag2[row - col + n - 1])
            continue;
        
        cols[col] = diag1[row + col] = diag2[row - col + n - 1] = true;
        
        solve(row + 1, board, cols, diag1, diag2);
        
        cols[col] = diag1[row + col] = diag2[row - col + n - 1] = false;
    }
}

void Vedant() {
    vector<string> board(n);
    for (int i = 0; i < n; i++) {
        cin >> board[i];
    }
    
    vector<bool> cols(n, false), diag1(2 * n - 1, false), diag2(2 * n - 1, false);
    result = 0;
    
    solve(0, board, cols, diag1, diag2);
    cout << result << endl;
}

int main() {
    fastio();
    int t = 1;
    while(t--){
       Vedant();
    }
    return 0;
}