제출 #313918

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
313918		phathnv	Wand (COCI19_wand)	C++11	70 / 70	128 ms	4856 KiB

wand

#include <bits/stdc++.h>

#define mp make_pair
#define X first
#define Y second
#define taskname "WAND"

using namespace std;

typedef long long ll;
typedef pair <int, int> ii;

const int N = 100001;

int n, m;
vector <int> adj[N];
bool vst[N];

void readInput(){
    cin >> n >> m;
    for(int i = 1; i <= m; i++){
        int u, v;
        cin >> u >> v;
        adj[v].push_back(u);
    }
}

void dfs(int u){
    for(int v : adj[u]){
        if (vst[v])
            continue;
        vst[v] = 1;
        dfs(v);
    }
}

void solve(){
    dfs(1);
    if (adj[1].empty())
        vst[1] = 1;
    for(int i = 1; i <= n; i++)
        cout << (vst[i]? '1' : '0');
}

int main(){
    if (fopen(taskname".inp", "r")){
        freopen(taskname".inp", "r", stdin);
        freopen(taskname".out", "w", stdout);
    }
    readInput();
    solve();
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

wand.cpp: In function 'int main()':
wand.cpp:47:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   47 |         freopen(taskname".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
wand.cpp:48:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   48 |         freopen(taskname".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 70 / 70