Submission #524804

#	Time	Username	Problem	Language	Result	Execution time	Memory
524804		qwerasdfzxcl	Mountains and Valleys (CCO20_day1problem3)	C++14	2 / 25	13 ms	12492 KiB

Main

#include <bits/stdc++.h>

typedef long long ll;
using namespace std;
vector<pair<int, int>> adj[500500];
int dist[500500];

void dfs(int s, int pa = -1){
    if (pa==-1) dist[s] = 0;
    else dist[s] = dist[pa] + 1;
    for (auto &v:adj[s]) if (v.first!=pa) dfs(v.first, s);
}

int main(){
    int n, m;
    scanf("%d %d", &n, &m);
    for (int i=0;i<m;i++){
        int x, y, z;
        scanf("%d %d %d", &x, &y, &z);
        if (z!=1) continue;
        adj[x].emplace_back(y, z);
        adj[y].emplace_back(x, z);
    }

    dfs(0);
    dfs(max_element(dist, dist+n)-dist);
    printf("%d\n", (n-1)*2 - *max_element(dist, dist+n));
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:16:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |     scanf("%d %d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~
Main.cpp:19:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |         scanf("%d %d %d", &x, &y, &z);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 1
• Subtask 2: 0 / 2
• Subtask 3: 2 / 2
• Subtask 4: 0 / 6
• Subtask 5: 0 / 2
• Subtask 6: 0 / 3
• Subtask 7: 0 / 5
• Subtask 8: 0 / 4