Submission #341200

#	Time	Username	Problem	Language	Result	Execution time	Memory
341200		IZhO_2021_I_want_Silver	Chessboard (IZhO18_chessboard)	C++14	39 / 100	80 ms	3436 KiB

chessboard

#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <set>
#include <map>
#include <iomanip>
#include <cassert>
#include <stack>
#include <queue>
#include <deque>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>-

using namespace std;
//using namespace __gnu_pbds;

typedef long long ll;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;

// template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
//  order_of_key (k) : Number of items strictly smaller than k .
//  find_by_order(k) : K-th element in a set (counting from zero).
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
#define pb push_back
#define ppb pop_back
#define mkp make_pair
#define F first
#define S second
#define lb lower_bound
#define ub upper_bound
#define show(a) cerr << #a <<" -> "<< a <<" "
#define nl cerr <<"\n"
//#define int ll

const int N = 2e5 + 5;
const int oo = 1e9 + 5;

int n, k, ans = oo, x[N], y[N], x2[N], y2[N];
vector <int> vec;

void solve() {
    cin >> n >> k;
    for (int i = 1; i <= k; ++i) {
        cin >> x[i] >> y[i] >> x2[i] >> y2[i];
        --x[i], --y[i], --x2[i], --y2[i];
    }
    for (int sz = 1; sz < n; ++sz) {
        if (n % sz == 0) { vec.pb(sz); }
    }
    for (int sz : vec) {
        int res1 = 0, res2 = 0;
        if ((n / sz) %  2 == 0) {
            res1 = n * sz * (n / sz / 2);
            res2 = (n * n) - res1;
            assert(res1 == res2);
        }
        else {
            res1 = n * sz * (n / sz / 2) + sz * sz * (n / sz / 2); // белый - черный - ...
            res2 = (n * n) - res1;
        }
        for (int i = 1; i <= k; ++i) {
            int bw = (x[i] / sz) + (y[i] / sz);
            if (bw % 2 == 0) {
                ++res1;
                --res2;
            }
            else {
                --res1;
                ++res2;
            }
        }
        ans = min(ans, min(res1, res2));
    }
    cout << ans;
}

 main () {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	int tests = 1;
	//cin >> tests;
	while (tests --) {
		solve();
	}
	return 0;
}
/*
    Just Chalish!
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
*/

Compilation message (stderr)

chessboard.cpp:80:8: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   80 |  main () {
      |        ^

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