Submission

PPPPPPPPPPPPPPPPPPPPPPPPPPPPPP

Score: 100

User: ftm

Problemset: Sirabyrinth 6

Language: cpp

Time: 0.009 second

Submitted On: 2025-03-06 13:03:10

#include<bits/stdc++.h>
using namespace std;
#define f(i,a,b,c) for(int i=a;i<=b;i+=c)
#define r(i,a,b,c) for(int i=a;i>=b;i-=c)
#define fi first
#define se second
#define pb push_back
using ll=long long int;
using pii=array<int,2>;
const int N=2e4+1;
const int M=1e9+7;
vector<pii> g[N];
int dp[N];

void dfs(int u, int p){
	for(auto e:g[u]){
		int v=e[0],w=e[1];
		if(v^p){
			dfs(v,u);
			dp[u]=max(dp[u],dp[v]+w);
		}
	}
}


int main(){
	ios::sync_with_stdio(0); cin.tie(0);
     int n,k;cin>>n>>k;
     ll ans=0;
     f(i,2,n,1){
     	int u,v,w;cin>>u>>v>>w;
     	g[u].pb({v,w});
     	g[v].pb({u,w});
     	ans+=w*2;
	 }
	 dfs(k,k);
	 ans-=dp[k];
	 cout<<ans;
}
/*
4 1
0 1 5
2 0 3
3 0 4

15
*/