Ruudukko

input/code.cpp: In function 'int main()':
input/code.cpp:27:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j = 0; j < v.size(); ++j) {
                          ^
input/code.cpp:36:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j = 0; j < v.size(); ++j) {
                          ^

#include <iostream>
#include <vector>
#define F first
#define S second
using namespace std;
const int MN = 510;
char t[MN][MN];
char ans[MN];
bool used[MN][MN];
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n;
    cin>>n;

    for(int i = 0; i < n; ++i) {
        for(int j = 0; j < n; ++j) {
            cin>>t[i][j];
        }
    }
    vector<pair<int, int> > v;
    vector<pair<int, int> > v2;
    v.push_back({0, 0});
    ans[0] = t[0][0];
    for(int i = 0; i < 2*n-2; ++i) {
        int mi = 1e9;
        for(int j = 0; j < v.size(); ++j) {
            if(v[j].F < n-1) {
                mi = min(mi, (int)t[v[j].F+1][v[j].S]);
            }
            if(v[j].S < n-1) {
                mi = min(mi, (int)t[v[j].F][v[j].S+1]);
            }
        }
        ans[i+1] = mi;
        for(int j = 0; j < v.size(); ++j) {
            if(v[j].F < n-1) {
                if(t[v[j].F+1][v[j].S] == mi && !used[v[j].F+1][v[j].S]) {
                    used[v[j].F+1][v[j].S] = 1;
                    v2.push_back({v[j].F+1, v[j].S});
                }
            }
            if(v[j].S < n-1) {
                if(t[v[j].F][v[j].S+1] == mi && !used[v[j].F][v[j].S+1]) {
                    used[v[j].F][v[j].S+1] = 1;
                    v2.push_back({v[j].F, v[j].S+1});
                }
            }
        }
        v = v2;
        v2.clear();
    }
    for(int i = 0; i < 2*n-1; ++i) {
        cout<<char(ans[i]);
    }
    cout<<'\n';


}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED