Submission #631479

#	Time	Username	Problem	Language	Result	Execution time	Memory
631479		bachhoangxuan	Pipes (BOI13_pipes)	C++17	41.48 / 100	202 ms	14644 KiB

pipes

#include<bits/stdc++.h>
using namespace std;
#define maxn 100005
#define pii pair<int,int>
vector<pii> edge[maxn];
int n,m,c[maxn],st,num=0,ans[maxn];
bool check[maxn],visited[maxn];
bool dfs(int u,int par){
    bool ok=false;visited[u]=true;
    for(pii x:edge[u]){
        int v=x.first;
        if(v==par) continue;
        if(visited[v]){st=v;ok=true;}
        else if(dfs(v,u)) ok=true;
    }
    if(ok){check[u]=true;num++;}
    if(st==u){st=0;return false;}
    if(ok) return true;
    return false;
}
void dfs2(int u,int par){
    for(pii v:edge[u]){
        if(v.first==par || check[v.first]) continue;
        dfs2(v.first,u);
        ans[v.second]=c[v.first];
        c[u]+=c[v.first];
    }
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);cout.tie(NULL);
    cin >> n >> m;
    if(m>n){
        cout << 0 << '\n';
        return 0;
    }
    for(int i=1;i<=n;i++) cin >> c[i];
    for(int i=1;i<=m;i++){
        int u,v;cin >> u >> v;
        edge[u].push_back({v,i});
        edge[v].push_back({u,i});
    }
    dfs(1,0);
    if(num%2==0 && m==n){
        cout << 0 << '\n';
        return 0;
    }
    for(int i=1;i<=n;i++){
        if(check[i]) dfs2(i,0);
    }
    if(m!=n) dfs2(1,0);
    int cur=0,u=0;
    for(int i=1;i<=n;i++){
        if(check[i]){cur=i;u=i;break;}
    }
    while(true){
        for(pii v:edge[u]){
            if(check[v.first]){
                ans[v.second]=c[u];
                c[v.first]+=c[u];
                u=v.first;
                break;
            }
        }
        if(u==cur) break;
    }
    for(int i=1;i<=m;i++) cout << ans[i]*2 << '\n';
}

• Subtask 1: 0 / 30
• Subtask 2: 41.48148148148148 / 70