Submission #1133833

#	Time	Username	Problem	Language	Result	Execution time	Memory
1133833		steveonalex	Chessboard (IZhO18_chessboard)	C++20	100 / 100	347 ms	1936 KiB

chessboard

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()

ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}

ll gcd(ll a, ll b){return __gcd(a, b);}
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ll mask){return __builtin_ctzll(mask);}
int logOf(ll mask){return __lg(mask);}

mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}

template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }

template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }

template <class T>
    void printArr(T& container, string separator = " ", string finish = "\n"){
        for(auto item: container) cout << item << separator;
        cout << finish;
    }


template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }
const ll INF = 1e18 + 69;

ll count_black_chess(ll k){
    return k * k / 2;
}

ll count_stuff(int i, int x, int y){
    if (min(x, y) == 0) return 0;
    int _x = x / i, _y = y / i;
    ll ans = 1LL * _x * _y / 2 * i * i;
    ans += 1LL * ((_x + _y % 2) / 2) * (y - _y * i) * i;
    ans += 1LL * ((_y + _x % 2) / 2) * (x - _x * i) * i;
    ans += 1LL * ((_x + _y) % 2) * (x - _x * i) * (y - _y * i);
    return ans;
}

ll go(int i, vector<array<int, 4>> &arr){ // count number of overlapped black squares
    ll ans = 0;
    for(auto j: arr){
        ans += count_stuff(i, j[2], j[3]);
        ans -= count_stuff(i, j[0]-1, j[3]);
        ans -= count_stuff(i, j[2], j[1]-1);
        ans += count_stuff(i, j[0]-1, j[1]-1);
    }
    return ans;
}

void solve(){
    int n, k; cin >> n >> k;
    vector<array<int, 4>> arr(k);
    for(int i = 0; i < k; ++i) for(int j = 0; j < 4; ++j) cin >> arr[i][j];

    ll tot_black = 0;
    for(auto &i: arr) {
        tot_black += 1LL * abs(i[3] - i[1] + 1) * abs(i[2] - i[0] + 1);
    }

    ll ans = INF;
    for(int i = 1; i < n; ++i){
        if (n % i == 0){
            ll cur = go(i, arr);
            ll black_cnt = 1LL * i * i * count_black_chess(n / i);
            minimize(ans, (black_cnt - cur) + (tot_black - cur));
            cur = tot_black - cur;
            black_cnt = 1LL * n * n - black_cnt;
            minimize(ans, (black_cnt - cur) + (tot_black - cur));
        }
    }
    cout << ans << "\n";
}

int main(void){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    clock_t start = clock();
    
    solve();

    cerr << "Time elapsed: " << clock() - start << "ms!\n";
    return 0;
}

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