제출 #1335463

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1335463		Hisu	Reachability (NOI25_reachability)	C++20	4 / 100	2 ms	580 KiB

Main

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
#define ed "\n"
#define int long long

const int N = 2e5 + 5;
int n, l[N], u[N], v[N];

namespace sub1 {
    bool check() {
        return n <= 7;
    }

    vector<int> adj[N];

    void dfs(int u, int pa, int &res) {
        res++;
        for(int v : adj[u]) {
            if(v == pa) continue;
            dfs(v, u, res);
        }
    }

    void backtrack(int pos) {
        if(pos >= n) {
            bool check = true;
            for(int i = 1; i <= n; i++) {
                int res = 0;
                dfs(i, 0, res);
                if(res != l[i]) check = false;
            }

            if(check == true) {
                cout << "YES";
                exit(0);
            }
            return;
        }

        adj[u[pos]].push_back(v[pos]);
        adj[v[pos]].push_back(u[pos]);
        backtrack(pos + 1);
        adj[u[pos]].pop_back();
        adj[v[pos]].pop_back();

        adj[u[pos]].push_back(v[pos]);
        backtrack(pos + 1);
        adj[u[pos]].pop_back();

        adj[v[pos]].push_back(u[pos]);
        backtrack(pos + 1);
        adj[v[pos]].pop_back();
        
        backtrack(pos + 1);
    }

    void solve() {
        backtrack(1);
        cout << "NO";
    }
}

void solve(int iTest) {
    cin >> n;
    for(int i = 1; i <= n; i++) cin >> l[i];
    for(int i = 1; i < n; i++) cin >> u[i] >> v[i];

    if(sub1::check()) sub1::solve();
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);

    #define TASK "main"
    if(fopen(TASK ".inp", "r")) {
        freopen(TASK ".inp", "r", stdin);
        freopen(TASK ".out", "w", stdout);
    }
    else if(fopen("main.inp", "r")) {
        freopen("main.inp", "r", stdin);
        freopen("main.out", "w", stdout);
    }

    int T = 1;
    // cin >> T;
    for(int iTest = 1; iTest <= T; iTest++) {
        solve(iTest);
    }
}

컴파일 시 표준 에러 (stderr) 메시지

Main.cpp: In function 'int main()':
Main.cpp:79:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   79 |         freopen(TASK ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:80:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   80 |         freopen(TASK ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:83:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |         freopen("main.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:84:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |         freopen("main.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 4 / 4
• Subtask 2: 0 / 5
• Subtask 3: 0 / 11
• Subtask 4: 0 / 10
• Subtask 5: 0 / 45
• Subtask 6: 0 / 25