Submission #328194

#	Time	Username	Problem	Language	Result	Execution time	Memory
328194		poom2904	Torrent (COI16_torrent)	C++11	69 / 100	140 ms	25452 KiB

torrent

#include <bits/stdc++.h>
using namespace std;
int n,a,b;
int x,y;
vector<int> edge[300001];
stack<int> stk;
vector<int> instk(300001,false);
vector<int> dis(300001,0);
int main()
{
    ios_base::sync_with_stdio(false);cin.tie(0);
    cin>>n>>a>>b;
    for(int i=1;i<n;i++)
    {
        cin>>x>>y;
        edge[x].push_back(y);
        edge[y].push_back(x);
    }
    queue<int> q;
    q.push(a);
    q.push(b);
    stk.push(a);
    stk.push(b);
    instk[a]=instk[b]=true;
    while(!q.empty())
    {
        int u = q.front();
        q.pop();
        for(auto v :edge[u])if(!instk[v])
        {
            stk.push(v);
            instk[v]=true;
            q.push(v);
        }
    }
    while(!stk.empty())
    {
        int u = stk.top();
        stk.pop();
        instk[u]=false;
        vector<int> vec;
        for(auto v : edge[u])if(!instk[v] && v!=a && v!=b)vec.push_back(dis[v]);
        sort(vec.begin(),vec.end(),greater<int>());
        int max_t=0;
        for(int i=0;i<vec.size();i++)max_t=max(max_t,vec[i]+i+1);
        dis[u]=max_t;
    }
    cout<<max(dis[a],dis[b]);
    return 0;
}

Compilation message (stderr)

torrent.cpp: In function 'int main()':
torrent.cpp:45:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |         for(int i=0;i<vec.size();i++)max_t=max(max_t,vec[i]+i+1);
      |                     ~^~~~~~~~~~~

• Subtask 1: 0 / 31
• Subtask 2: 69 / 69