Submission #342875

#	Time	Username	Problem	Language	Result	Execution time	Memory
342875		Rakhmand	Chessboard (IZhO18_chessboard)	C++14	70 / 100	487 ms	3564 KiB

chessboard

//
//  main.cpp
//  torelax
//
//  Created by Rakhman on 11/15/20.
//

#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <queue>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cassert>
#include <iterator>

#define ios ios_base::sync_with_stdio(0), cout.tie(0), cin.tie(0);
#define S second
#define F first
#define pb push_back
#define nl '\n'
#define NL cout << '\n';
#define EX exit(0)
#define all(s) s.begin(), s.end()
#define no_answer {cout << "NO"; exit(0);}
#define FOR(i, start, finish, k) for(llong i = start; i <= finish; i += k)

const long long mxn = 1e5 + 110;
const long long mnn = 1e3 + 2;
const long long mod = 1e9 + 7;
const long long inf = 1e18;
const long long OO = 1e9;

typedef long long llong;
typedef unsigned long long ullong;

using namespace std;

llong n, k;
llong ans = inf;

struct dot{
    llong left, up, right, down;
}b[mxn];

llong get_color(llong x, llong y, llong d){
    return (((x - 1) / d) + ((y - 1) / d)) % 2;
}

llong get(llong d){
    //left-corner is black
    llong blacks = d * d * (n / d) * (n / d / 2);
    if((n / d) % 2 == 1){
        blacks += d * d * (n / d / 2 + 1);
    }
    llong paint = 0;
    llong blacks1 = n * n - blacks;
    for(int i = 1; i <= k; i++){
        int x = b[i].left, y = b[i].up;
        if(get_color(x, y, d) == 0){
            blacks--;
        }else{
            paint++;
        }
    }
    //left-corner is white
    llong paint1 = 0;
    for(int i = 1; i <= k; i++){
        int x = b[i].left, y = b[i].up;
        if(get_color(x, y, d) == 1){
            blacks1--;
        }else{
            paint1++;
        }
    }
    return min(blacks1 + paint1, blacks + paint);
}

int main() {
    ios;
    cin >> n >> k;
    for(int i = 1; i <= k; i++){
        cin >> b[i].left >> b[i].up >> b[i].right >> b[i].down;
    }
    for(int i = 1; i <= sqrt(n); i++){
        if(n % i == 0){
            ans = min(ans, get(i));
            if(n / i != i && i != 1){
                ans = min(get(n / i), ans);
            }
        }
    }
    cout << ans;
}


/*
 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
 
 */

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