Submission #495039

#	Time	Username	Problem	Language	Result	Execution time	Memory
495039		armashka	Chessboard (IZhO18_chessboard)	C++17	23 / 100	1 ms	460 KiB

chessboard

#include <bits/stdc++.h>

//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
 
#define fast ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
#define all(v) v.begin(),v.end()
#define pb push_back
#define sz size()
#define ft first
#define sd second
 
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef unsigned long long ull;

const int N = 1e6 + 5;
const ll M = 1e8;
const ll inf = 1e9;
const ll mod = 1e9;
const double Pi = acos(-1); 

ll binpow(ll x, ll ti) { ll res = 1;while (ti){if(ti & 1)res *= x;x *= x;ti >>= 1; x %= mod; res %= mod;} return res;}
ll binmul(ll x, ll ti) { ll res = 0;while (ti){if(ti & 1)res += x;x += x;ti >>= 1; x %= mod; res %= mod;} return res;}
ll nok(ll a, ll b) { return (a*b)/__gcd(abs(a),abs(b)) * (a*b > 0 ? 1 : -1); }
bool odd(ll n) { return (n % 2 == 1); }
bool even(ll n) { return (n % 2 == 0); }            
                                                                    
int n, k, ans = inf;
bool bl[105][105], col[105][105];

void check(int razmer) {
	for (int i = 1; i <= n; ++ i)
		for (int j = 1; j <= n; ++ j) col[i][j] = 0;
	
	int cnt = 0;
	for (int i = 1; i <= n; ++ i) {
		for (int j = 1; j <= n; ++ j) {
			int num = ((i - 1) / razmer) + ((j - 1) / razmer);
			if (even(num) && !bl[i][j]) ++ cnt;
			if (odd(num) && bl[i][j]) ++ cnt; 
		}
	}
	//cout << razmer << " " << min(cnt, n * n - cnt) << "\n";
	ans = min(ans, min(cnt, n * n - cnt));
	return;
}

const void solve(/*Armashka*/) {
	cin >> n >> k;
	for (int i = 1; i <= k; ++ i) {
		int x1, y1, x2, y2;
		cin >> x1 >> y1 >> x2 >> y2;
		for (int i = y1; i <= y2; ++ i) {
			for (int j = x1; j <= x2; ++ j) bl[i][j] = 1;
		}
	}
	for (int i = 1; i * i <= n; ++ i) {
		if (n % i == 0) {
			check(i);
			if (n / i != i && i > 1) check(n / i);
		}
	}
	cout << ans << "\n";
}

signed main() {
    fast;
	//freopen("divide.in", "r", stdin);
	//freopen("divide.out", "w", stdout);
    int tt = 1;
    //cin >> tt;
    while (tt --) {
    	solve();
	}
}

/*

6 8
3 3 3 3
1 2 1 2
3 4 3 4
5 5 5 5
4 3 4 3
4 4 4 4
2 1 2 1
3 6 3 6

*/

/*
9 12
1 9 4
1 2 5
2 3 7
2 4 3
4 3 6
3 6 4
8 7 10
6 7 5
5 8 1
9 5 7
5 4 12
6 8 2
2
4 7
5
1 6
5 3
4 8
5 8
1 5

*/

• Subtask 1: 8 / 8
• Subtask 2: 0 / 8
• Subtask 3: 15 / 15
• Subtask 4: 0 / 16
• Subtask 5: 0 / 23
• Subtask 6: 0 / 30