제출 #285379

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
285379		ScarletS	Pipes (BOI13_pipes)	C++17	74.07 / 100	231 ms	16888 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], counter[MAXN];
bool done[MAXN];
//set<pii> vals[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<<0;
        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,x=0;
    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<<0;
        return 0;
    }
    stack<int> st;
    for (int i=1;i<=n;++i)
    {
        counter[i]=sz(edges[i]);
        if (counter[i]==1)
            st.push(i);
    }
    while (sz(st))
    {
        ++x;
        v=st.top();st.pop();
        done[v]=1;
        for (pii i : edges[v])
            if (!done[i.f])
            {
                u=i.s;
                ans[u]=scores[v]-cur[v];
                cur[v]+=ans[u];
                cur[i.f]+=ans[u];
                --counter[i.f];
                if (counter[i.f]==1)
                    st.push(i.f);
            }
    }
    if ((n-x+1)&1)
    {
        cout<<0;
        return 0;
    }
    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 44.074074074074076 / 70