Submission #855136

#	Time	Username	Problem	Language	Result	Execution time	Memory
855136		coffee5427	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	1394 ms	102180 KiB

joioi

#include <bits/stdc++.h>
#define int long long

using namespace std;

const int INF = 2e18;
const int MAXN = 2e3 + 5;
int n, m, mx, mn;
int a[MAXN][MAXN];
int g[MAXN][MAXN];

void rotate() {
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            g[j][n - i + 1] = a[i][j];
        }
    }
    swap(n, m);
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            a[i][j] = g[i][j];
        }
    }
}

bool check(int x) {
    int lim = m + 1;
    for (int i = 1; i <= n; i++) {
        int r = 0;
        for (int j = 1; j <= min(lim, m); j++) {
            if (mx - x <= a[i][j]) {
                r = max(r, j);
            } else {
                break;
            }
        }
        lim = r;
        for (int j = r + 1; j <= m; j++) {
            if (a[i][j] - x > mn) {
                return false;
            }
        }
    }
    return true;
}

int search() {
    int l = 0, r = 2e9 + 5;
    while (l < r) {
        int mid = (l + r) >> 1;
        if (check(mid)) {
            r = mid;
        } else {
            l = mid + 1;
        }
    }
    return r;
}

signed main() {
    cin >> n >> m;
    mx = -INF, mn = INF;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            cin >> a[i][j];
            mx = max(mx, a[i][j]);
            mn = min(mn, a[i][j]);
        }
    }

    int ans = INF;
    ans = min(ans, search());
    rotate();
    ans = min(ans, search());
    rotate();
    ans = min(ans, search());
    rotate();
    ans = min(ans, search());

    ans = min(mx - mn, ans);
    cout << ans << "\n";
}

• Subtask 1: 15 / 15
• Subtask 2: 45 / 45
• Subtask 3: 40 / 40