Submission #1186732

#	Time	Username	Problem	Language	Result	Execution time	Memory
1186732		sasde	Pipes (BOI13_pipes)	C++20	74.07 / 100	76 ms	68168 KiB

pipes

#include<bits/stdc++.h>
#define task "strdel"
#define int long long
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii,ii>
#define se second
#define fi first
#define ffi fi.fi
#define sfi se.fi
#define sse se.se
#define fse fi.se
#define lt(i, c, d) for(int i = c; i <= d; ++i)
#define fl(i, c, d) for(int i = d; i >= c; --i)
#define pb push_back
#define emb emplace_back
#define emf emplace_front
#define em emplace
using namespace std;
const int N=1e6+5,lg=20,mod=1e9+7;
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int Rand(int u,int v){
 return u+rd()%(v-u+1);
}
int c[N],m,n,sum,gg,ans[N],d[N];
set<ii>a[N];
bool k[N],k1[N];
void dfs(int u,int i){
  k[u]=true;
  sum+=c[u]*i;
  for(ii v:a[u]){
    if(!k[v.fi]){
      gg=v.se;
      dfs(v.fi,i*-1);
    }
  }
}
ii b[N];
void solve(){
    cin >> n >> m;
    if(m>n){
      cout <<0;return;
    }
    for(int i=1;i<=n;++i)cin >> c[i],d[i]=c[i];
        for(int i=1;i<=m;++i){
            int u,v;
            cin >> u >> v;
            a[u].insert({v,i});
            b[i]={u,v};
            a[v].insert({u,i});
        }
    int sl=0;
    queue<int>p;
    for(int i=1;i<=n;++i){
      if(a[i].size()==1){
        p.push(i);
        k[i]=true;
        // cout <<i<<" ";
      }
    }
    int cnt=0;
    while(!p.empty()){
      int u=p.front();
      p.pop();++cnt;
      if(a[u].size()){
        ii v=*a[u].begin();
        a[u].erase(v);
        a[v.fi].erase({u,v.se});

        ans[v.se]+=c[u];
        c[v.fi]-=c[u];
        if(a[v.fi].size()==1&&!k[v.fi]){
          k[v.fi]=true;
          p.push(v.fi);
        }
      }
    }

    if(cnt!=n&&(n-cnt)%2==0){
      cout <<0;return;
    }
    int st=0;
    for(int i=1;i<=n;++i){
      if(!k[i])st=i;
    }

    dfs(st,1);
    ans[gg]=sum/2;
    int u=b[gg].fi;
    int v=b[gg].se;
    k1[gg]=true;
    c[u]-=ans[gg];
    c[v]-=ans[gg];
    p.push(u);
    p.push(v);
    while(!p.empty()){
      int u=p.front();
      p.pop();
      for(ii v:a[u]){
        if(!k1[v.se]){
          ans[v.se]=c[u];
          c[v.fi]-=c[u];
          // cout <<v.se<<" ";
          k1[v.se]=true;
          p.push(v.fi);
        }
      }
    }
for(int i=1;i<=m;++i){
  d[b[i].fi]-=ans[i];
  d[b[i].se]-=ans[i];
}
    for(int i=1;i<=n;++i){
      if(d[i]!=0){
        cout <<0;return;
      }
    }
    for(int i=1;i<=m;++i)cout <<2*ans[i]<<'\n';

    
}
main()
{
  srand(time(0));
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    if(fopen(task".inp","r")){
      freopen(task".inp","r",stdin);
      freopen(task".out","w",stdout);
    }
    int t=1;
 //   cin >> t;
while(t--){
    solve();
    // cout<<'\n';
}

}

Compilation message (stderr)

pipes.cpp:122:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  122 | main()
      | ^~~~
pipes.cpp: In function 'int main()':
pipes.cpp:129:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  129 |       freopen(task".inp","r",stdin);
      |       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
pipes.cpp:130:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  130 |       freopen(task".out","w",stdout);
      |       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 44.0741 / 70