Submission #671102

#	Time	Username	Problem	Language	Result	Execution time	Memory
671102		GrandTiger1729	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	2143 ms	46576 KiB

joioi

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

const int INF = 1e9 + 9;
int main(){
    cin.tie(0)->sync_with_stdio(0);
    int n, m; cin >> n >> m;
    vector<vector<int>> a(n, vector<int>(m));
    int minn = INF, px = 0, py = 0;
    for (int i = 0; i < n; i++){
        for (int j = 0; j < m; j++){
            cin >> a[i][j];
            if (a[i][j] < minn){
                minn = a[i][j];
                px = i, py = j;
            }
        }
    }
    auto check = [&](int x) -> bool {
        auto _check = [&]() -> bool {
            vector<vector<bool>> tag(n, vector<bool>(m));
            for (int i = 0; i < n; i++){
                for (int j = 0; j < m; j++){
                    if (a[i][j] > minn + x){
                        tag[i][j] = 1;
                    }
                }
            }
            vector<vector<bool>> vis(n, vector<bool>(m));
            int maxn = m;
            for (int i = 0; i < n; i++){
                for (int j = 0; j < maxn; j++){
                    if (tag[i][j]){
                        maxn = j;
                        break;
                    }
                    vis[i][j] = 1;
                }
            }
            if (!vis[px][py]) return false;
            int mn = INF, mx = -INF;
            for (int i = 0; i < n; i++){
                for (int j = 0; j < m; j++){
                    if (!vis[i][j]){
                        mn = min(mn, a[i][j]);
                        mx = max(mx, a[i][j]);
                    }
                }
            }
            return mx - mn <= x;
        };
        bool ret = 0;
        for (int t = 0; t < 2; t++){
            ret |= _check();
            reverse(a.begin(), a.end());
            px = n - 1 - px;
            ret |= _check();
            for (int i = 0; i < n; i++){
                reverse(a[i].begin(), a[i].end());
            }
            py = m - 1 - py;
        }
        return ret;
    };
    int l = -1, r = INF;
    while (l < r - 1){
        int mid = (l + r) / 2;
        if (check(mid)){
            r = mid;
        }else{
            l = mid;
        }
    }
    cout << r;
    return 0;
}

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