Submission #1209515

#	Time	Username	Problem	Language	Result	Execution time	Memory
1209515		cpdreamer	Naboj (COCI22_naboj)	C++20	110 / 110	340 ms	15680 KiB

naboj

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
void file(){
    freopen("input.txt.txt","r",stdin);
    freopen("output.txt.txt","w",stdout);
}
const ll mod=(ll)1e9+7;
#define V vector
#define P pair
#define F first
#define S second
#define all(v) v.begin(),v.end()
#define pb push_back
bool guess(int a, int b) {
    cout << "? " << a << ' ' << b << endl;
    bool res;
    cin >> res;
    return res;
}
V<int>adj[(int)2e5+1];
stack<int>st;
bool flag=true;
void dfs(int  n,int state[]){
    if(state[n]==1){
        flag=false;
        return;
    }
    if(state[n]==2){
        return;
    }
    state[n]=1;
    for(auto u:adj[n]){
        dfs(u,state);
    }
    state[n]=2;
    st.push(n);
}
void solve(){
    int n;
    cin>>n;
    int m;
    cin>>m;
    for(int i=0;i<m;i++){
        int a,b;
        cin>>a>>b;
        adj[b].pb(a);
    }
    int state[n+1];
    memset(state,0,sizeof(state));
    for(int i=1;i<=n;i++){
        if(state[i]==0){
            dfs(i,state);
            if(!flag){
                cout<<-1<<endl;
                return;
            }
        }
    }
    cout<<n<<endl;
    while(!st.empty()){
        cout<<st.top()<<" "<<1<<endl;
        st.pop();
    }
}
int main() {
   // file();
    solve();
    return 0;
}

Compilation message (stderr)

naboj.cpp: In function 'void file()':
naboj.cpp:5:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 |     freopen("input.txt.txt","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
naboj.cpp:6:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    6 |     freopen("output.txt.txt","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 25 / 25
• Subtask 3: 70 / 70