Road network

input/code.cpp: In function 'void DFS(int, int)':
input/code.cpp:11:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 for(int i=0;i<somsiad[x].size();++i){
             ~^~~~~~~~~~~~~~~~~~

#include <bits/stdc++.h>

using namespace std;

vector<int> somsiad[100010];
int odw[100010];
int licz=0;
void DFS(int x,int st){
odw[x]=st;
licz++;
for(int i=0;i<somsiad[x].size();++i){
    if(odw[somsiad[x][i]]!=st)DFS(somsiad[x][i],st);
}
}

int main()
{
    int n,m;
    cin >> n >> m;
    int a,b;
    for(int i=0;i<m;++i)
    {
        cin >> a >> b;
        somsiad[a].push_back(b);
    }
    bool przerwany=false;
    for(int j=1;j<=n && przerwany==false ;++j){
        licz=0;
        DFS(j,j);
        if(licz<n){
        cout << "NO" << endl;
        przerwany=true;
        for(int i=1;i<=n;++i){
            if(odw[i]!=j && i!=j){
                    cout << j << " " << i << endl;
                    break;
            }
        }
    }
    }
    if(przerwany==false) cout << "YES" << endl;
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: TIME LIMIT EXCEEDED

Test 7

Verdict: TIME LIMIT EXCEEDED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: TIME LIMIT EXCEEDED

Test 10

Verdict: TIME LIMIT EXCEEDED

Test 11

Verdict: ACCEPTED