Submission #285370

#	Time	Username	Problem	Language	Result	Execution time	Memory
285370		ScarletS	Pipes (BOI13_pipes)	C++17	30 / 100	228 ms	17272 KiB

pipes

#include <bits/stdc++.h>
#define ll long long
#define sz(x) (int)(x).size()
#define pii pair<int,int>
#define f first
#define s second
using namespace std;

const int MAXN=1e5+10;
int n,m;
vector<pii> edges[MAXN];
int scores[MAXN], cur[MAXN], ans[5*MAXN];

void dfsTree(int c, int p, int x)
{
    for (pii i : edges[c])
        if (i.f!=p)
        {
            dfsTree(i.f,c,i.s);
            cur[c]+=ans[i.s];
        }
    if (c!=1)
    {
        ans[x]=scores[c]-cur[c];
        cur[c]+=ans[x];
    }
}

void treeCase()
{
    dfsTree(1,0,0);
    if (scores[1]!=cur[1])
    {
        cout<<"-1\n";
        return;
    }
    for (int i=0;i<m;++i)
        cout<<ans[i]*2<<"\n";
} 

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
    int u,v;
    cin>>n>>m;
    for (int i=1;i<=n;++i)
        cin>>scores[i];
    for (int i=0;i<m;++i)
    {
        cin>>u>>v;
        edges[u].push_back({v,i});
        edges[v].push_back({u,i});
    }
    if (m==n-1)
    {
        treeCase();
        return 0;
    }
    if (m>n)
    {
        cout<<"-1";
        return 0;
    }
    return 0;
}

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