#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pb push_back
#define maxn 300005
int N, K, low[maxn];
vector<int> adj[maxn], rev[maxn];
void init(int n, int k){
N = n, K = k;
for(int i = 0; i < k - 1; ++i) adj[i].pb(i + 1), rev[i + 1].pb(i);
for(int i = 0; i < n; ++i) low[i] = i;
}
int add_teleporter(int u, int v){
if(u == v){
if(u < K) return 1;
else return 0;
}
adj[u].pb(v);
rev[v].pb(u);
if(low[v] >= K) return 0;
queue<int> bfs; bfs.push(v);
while(bfs.size()){
int a = bfs.front(); bfs.pop();
for(auto b:rev[a]){
if(b == low[a] && b < K) return 1;
if(low[b] > low[a]) {
low[b] = low[a];
bfs.push(b);
}
if(low[b] < b && b < K) return 1;
}
}
return 0;
}
int main(){
int n, m, k; cin >> n >> m >> k;
init(n, k);
bool ok = 1;
for(int i = 0; i < m; ++i){
int u, v; cin >> u >> v;
if(add_teleporter(u, v)) {
cout << i << '\n';
ok = 0;
break;
}
}
if(ok) cout << m << '\n';
}
Compilation message
/usr/bin/ld: /tmp/cc2V8M4r.o: in function `main':
stub.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/cc5f6wQq.o:game.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status
