Submission #892993

#	Time	Username	Problem	Language	Result	Execution time	Memory
892993		vjudge1	Chessboard (IZhO18_chessboard)	C++17	47 / 100	132 ms	9240 KiB

chessboard

// 以上帝的名义
// 候选硕士
#include <bits/stdc++.h>

#ifdef local
#include "algo/debug.h"
#else
#define dbg(x...) 0
#endif

using namespace std ;
using ll = long long ;

bool isPrime(int x) {
    if (x < 2) return 0 ;
    for (int i = 2 ; i * i <= x ; i++) {
        if (x  % i == 0) {
            return 0 ;
        }
    }
    return 1 ;
}

int32_t main() {
    cin.tie(0)->sync_with_stdio(false) ;
    ll n, k ; cin >> n >> k ;
    struct rect {
        int x1, y1, x2, y2;
        void read() {
            cin >> x1 >> y1 >> x2 >> y2 ;
            x1--, y1-- , x2-- , y2-- ;
        }
    };
    vector<rect> a(k) ;
    for (int i = 0 ; i < k ; i++) a[i].read() ;
    vector<int> d;
    for (int i = 1 ; i * i <= n ; i++) {
        if (n % i) continue ;
        d.push_back(i) ;
        if (n / i != i) d.push_back(n / i) ;
    }
    auto calc = [&](ll del) -> ll{
        vector<vector<ll>> cnt(n, vector<ll>(2, 0)) ;
        int block = n / del ;
        for (int i = 0 ; i < k ; i++) {
            int x1 = a[i].x1 , y1 = a[i].y1 , x2 = a[i].x2, y2 = a[i].y2 ;
            cnt[x1 / block][(y1 / block) % 2]++;
        }
        dbg(cnt) ;
        ll ret = 0 , sum = 0 ;
        for (int i = 0 ; i < del ; i++) {
//            for (int j = 0 ; j < del ; j++) {
                if (i % 2 == 0) {
                    ll c = ((del + 1) / 2) * (block * block) ;
                    ll cur = c - cnt[i][0] + cnt[i][1] ;
                    sum += cur ;
                } else {
                    ll c = (del / 2) * (block * block) ;
                    ll cur = c - cnt[i][1] + cnt[i][0] ;
                    sum += cur ;
                }
//            }
        }
        ret = sum ;
        sum = 0 ;
        for (int i = 0 ; i < del ; i++) {
//            for (int j = 0 ; j < del ; j++) {
                if (i % 2 != 0) {
                    ll c = ((del + 1) / 2) * (block * block) ;
                    ll cur = c - cnt[i][0] + cnt[i][1] ;
                    sum += cur ;
                } else {
                    ll c = (del / 2) * (block * block) ;
                    ll cur = c - cnt[i][1] + cnt[i][0] ;
                    sum += cur ;
                }
//            }
        }
        ret = min(ret, sum) ;
        return ret ;
    };
    ll ret = LLONG_MAX ;
    for (int i : d) {
        dbg(i, calc(i)) ;
        if (i > 1)
            ret = min(ret, calc(i)) ;
    }
    cout << ret ;
    return 0 ;
}

// 希望白银

Compilation message (stderr)

chessboard.cpp: In lambda function:
chessboard.cpp:46:47: warning: unused variable 'x2' [-Wunused-variable]
   46 |             int x1 = a[i].x1 , y1 = a[i].y1 , x2 = a[i].x2, y2 = a[i].y2 ;
      |                                               ^~
chessboard.cpp:46:61: warning: unused variable 'y2' [-Wunused-variable]
   46 |             int x1 = a[i].x1 , y1 = a[i].y1 , x2 = a[i].x2, y2 = a[i].y2 ;
      |                                                             ^~
chessboard.cpp:8:19: warning: statement has no effect [-Wunused-value]
    8 | #define dbg(x...) 0
      |                   ^
chessboard.cpp:49:9: note: in expansion of macro 'dbg'
   49 |         dbg(cnt) ;
      |         ^~~
chessboard.cpp: In function 'int32_t main()':
chessboard.cpp:8:19: warning: statement has no effect [-Wunused-value]
    8 | #define dbg(x...) 0
      |                   ^
chessboard.cpp:84:9: note: in expansion of macro 'dbg'
   84 |         dbg(i, calc(i)) ;
      |         ^~~

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