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Submission #680440

# Submission time Handle Problem Language Result Execution time Memory
680440 2023-01-10T21:03:48 Z qwerasdfzxcl Wells (CEOI21_wells) C++17
0 / 100
 37 ms 71896 KB 
#include <bits/stdc++.h>

typedef long long ll;
using namespace std;
int dist[10010][10010], vcnt, n, k;
vector<int> adj[1501500], G[1501500], st;
vector<vector<int>> path;

void dfs(int s, int pa = -1){
    st.push_back(s);
    if ((int)st.size()==k) path.push_back(st);
    dist[st[0]][s] = (int)st.size() - 1;

    for (auto &v:adj[s]) if (v!=pa){
        dfs(v, s);
    }

    st.pop_back();
}

int col[1501500];
int simulate(int s){
    vector<int> q = {s}, ch = {s};
    col[s] = 1;

    while(!q.empty()){
        int v = q.back(); q.pop_back();
        for (int i=1;i<=n;i++) if (dist[v][i]==k && !col[i]){
            col[i] = 1;
            q.push_back(i);
            ch.push_back(i);
        }
    }

    int ret = 1;
    for (auto &p:path){
        int cnt = 0;
        for (auto &x:p) if (col[x]) cnt++;
        if (cnt>1){
            for (auto &x:ch) col[x] = 0;
            return 0;
        }

        if (cnt==0) ret = -1;
    }


    return ret;
}

int main(){
    scanf("%d %d", &n, &k);
    for (int i=1;i<=n-1;i++){
        int x, y;
        scanf("%d %d", &x, &y);
        adj[x].push_back(y);
        adj[y].push_back(x);
    }

    for (int i=1;i<=n;i++){
        dfs(i);
    }

    for (int i=1;i<=n;i++) if (simulate(i)==1){
        printf("YES\n0\n");
        return 0;
    }

    printf("NO\n0\n");
    return 0;
}

Compilation message

wells.cpp: In function 'int main()':
wells.cpp:52:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |     scanf("%d %d", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~
wells.cpp:55:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   55 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0.0 / 30.0

# Verdict Execution time Memory Grader output
1 Partially correct 33 ms 70760 KB Output is partially correct
2 Incorrect 37 ms 71896 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0.0 / 20.0

# Verdict Execution time Memory Grader output
1 Partially correct 33 ms 70760 KB Output is partially correct
2 Incorrect 37 ms 71896 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0.0 / 20.0

# Verdict Execution time Memory Grader output
1 Partially correct 33 ms 70760 KB Output is partially correct
2 Incorrect 37 ms 71896 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
0.0 / 30.0

# Verdict Execution time Memory Grader output
1 Partially correct 33 ms 70760 KB Output is partially correct
2 Incorrect 37 ms 71896 KB Output isn't correct
3 Halted 0 ms 0 KB -