Thin Ice

input/code.cpp: In function 'int main()':
input/code.cpp:92:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<node>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   92 |     for (int i = 0; i < L.size(); i++) {
      |                     ~~^~~~~~~~~~

#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<unordered_set>

using namespace std;

#define vi vector<int>
#define vvi vector<vi>
#define vn vector<node>
#define vvn vector<vn>
#define vvvn vector<vvn>
#define pi pair<int, int>
#define sn unordered_set<node>
#define pq priority_queue<node, vector<node>, comp>

struct node {
    int x, y;
};

vvi B, V;
int n, m;

class comp {
    public:
    bool operator()(node a, node b) {
        if (a.x < 0 || a.y < 0 || a.x >= n || a.y >= m) return 1;
        if (b.x < 0 || b.y < 0 || b.x >= n || b.y >= m) return 0;
        return B[a.x][a.y] < B[b.x][b.y];
    }
};

bool comp2(node a, node b) {
    return B[a.x][a.y] > B[b.x][b.y];
}

vn L;
pq Q;


int oink(int x, int y) {
    V.clear();
    while(!Q.empty()) Q.pop();
    V.resize(n, vi(m, 0));
    Q.push({x,y});
    int t = 0, k = B[x][y]+1, a = B[x][y], t2 = 0;
    //cerr << "\n";
    while(!Q.empty()) {
        auto b = Q.top();
        Q.pop();
        if (b.x < 0 || b.y < 0 || b.x >= n || b.y >= m) continue;
        if (V[b.x][b.y]) continue;
        t++;
        t2++;
        if (k > B[b.x][b.y]) {
            t -= k - B[b.x][b.y];
            k = B[b.x][b.y];
            if (t < 0) {
                a += t;
                t = 0;
            }
        }
        //cerr << b.x << " " << b.y << " " << t << " " << k << " " << a << " " << t2 << endl;
        V[b.x][b.y] = 1;
        if (t2 >= a) return a;
        Q.push({b.x-1, b.y});
        Q.push({b.x+1, b.y});
        Q.push({b.x, b.y-1});
        Q.push({b.x, b.y+1});
    }
    return t2;
}

int main() {
    cin >> n >> m;
    B.resize(n, vi(m));
    for (int i = 0; i < n; i++) {
        for (auto &j : B[i]) cin >> j;
    }
    for (int i = 0; i < n; i++) {
        L.push_back({i, 0});
        L.push_back({i, m-1});
    }
    for (int i = 1; i < m-1; i++) {
        L.push_back({0, i});
        L.push_back({n-1, i});
    }
    sort(L.begin(), L.end(), comp2);
    int m = 0;
    bool q = 1;
    for (int i = 0; i < L.size(); i++) {
        int x = L[i].x, y = L[i].y;
        if (m >= B[x][y]) {
            cout << m << endl;
            q = 0;
            break;
        }
        m = max(oink(x, y), m);
    }
    if (q) cout << m << endl;
}

Test 1

Group: 1, 5, 6

Verdict: ACCEPTED

Test 2

Group: 1, 5, 6

Verdict: ACCEPTED

Test 3

Group: 1, 5, 6

Verdict: ACCEPTED

Test 4

Group: 1, 5, 6

Verdict: ACCEPTED

Test 5

Group: 1, 5, 6

Verdict: ACCEPTED

Test 6

Group: 1, 5, 6

Verdict: ACCEPTED

Test 7

Group: 1, 5, 6

Verdict: ACCEPTED

Test 8

Group: 1, 5, 6

Verdict: ACCEPTED

Test 9

Group: 1, 2, 5, 6

Verdict: ACCEPTED

Test 10

Group: 2, 6

Verdict: ACCEPTED

Test 11

Group: 2, 6

Verdict: ACCEPTED

Test 12

Group: 2, 6

Verdict: ACCEPTED

Test 13

Group: 2, 6

Verdict: ACCEPTED

Test 14

Group: 2, 6

Verdict: ACCEPTED

Test 15

Group: 2, 6

Verdict: ACCEPTED

Test 16

Group: 2, 6

Verdict: ACCEPTED

Test 17

Group: 2, 6

Verdict: ACCEPTED

Test 18

Group: 2, 6

Verdict: ACCEPTED

Test 19

Group: 2, 6

Verdict: ACCEPTED

Test 20

Group: 2, 6

Verdict: TIME LIMIT EXCEEDED

Test 21

Group: 2, 6

Verdict: ACCEPTED

Test 22

Group: 3, 4, 5, 6

Verdict: ACCEPTED

Test 23

Group: 3, 4, 5, 6

Verdict: ACCEPTED

Test 24

Group: 3, 4, 5, 6

Verdict: ACCEPTED

Test 25

Group: 3, 4, 5, 6

Verdict: ACCEPTED

Test 26

Group: 3, 4, 5, 6

Verdict: ACCEPTED

Test 27

Group: 3, 4, 5, 6

Verdict: ACCEPTED

Test 28

Group: 4, 6

Verdict: TIME LIMIT EXCEEDED

Test 29

Group: 4, 6

Verdict: TIME LIMIT EXCEEDED

Test 30

Group: 4, 6

Verdict: TIME LIMIT EXCEEDED

Test 31

Group: 4, 6

Verdict: TIME LIMIT EXCEEDED

Test 32

Group: 4, 6

Verdict: ACCEPTED

Test 33

Group: 4, 6

Verdict: ACCEPTED

Test 34

Group: 4, 6

Verdict: TIME LIMIT EXCEEDED

Test 35

Group: 5, 6

Verdict: ACCEPTED

Test 36

Group: 5, 6

Verdict: ACCEPTED

Test 37

Group: 5, 6

Verdict: ACCEPTED

Test 38

Group: 5, 6

Verdict: ACCEPTED

Test 39

Group: 5, 6

Verdict: ACCEPTED

Test 40

Group: 5, 6

Verdict: ACCEPTED

Test 41

Group: 5, 6

Verdict: ACCEPTED

Test 42

Group: 6

Verdict: TIME LIMIT EXCEEDED

Test 43

Group: 6

Verdict: TIME LIMIT EXCEEDED

Test 44

Group: 6

Verdict: TIME LIMIT EXCEEDED

Test 45

Group: 6

Verdict: TIME LIMIT EXCEEDED

Test 46

Group: 6

Verdict: ACCEPTED

Test 47

Group: 6

Verdict: ACCEPTED

Test 48

Group: 6

Verdict: TIME LIMIT EXCEEDED