Submission #1186742

#	Time	Username	Problem	Language	Result	Execution time	Memory
1186742		sasde	Pipes (BOI13_pipes)	C++20	74.07 / 100	81 ms	66484 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],s[N];
set<ii>a[N];
bool k[N];
vector<int>cir,ed;
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;
      auto v=*a[u].begin();
      c[v.fi]-=c[u];
      ans[v.se]+=c[u];
      a[v.fi].erase({u,v.se});
      if(a[v.fi].size()<2&&!k[v.fi]){
        p.push(v.fi);
        k[v.fi]=1;
      }
    }

    if((n-cnt)%2==0){
      cout <<0;return;
    }
    int st=0;
    for(int i=1;i<=n;++i){
      if(!k[i])st=i;
    }
    int u=st;
    while(cir.empty()||u!=st){
      ii v=(cir.empty()||(*a[u].begin()).fi!=cir.back()?*(a[u].begin()):*(a[u].rbegin()));
      cir.emb(u);
      ed.emb(v.se);
      u=v.fi;
    }
    for(int i=cir.size()-1;i>=0;--i){
      s[i]=c[cir[i]]-s[i+1];
    }
    int pr=0;
    for(int i=0;i<cir.size();++i){
      pr=c[cir[i]]-pr;
      ans[ed[i]]=(s[i]+pr)/2;
    }
    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:93:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   93 | main()
      | ^~~~
pipes.cpp: In function 'int main()':
pipes.cpp:100:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  100 |       freopen(task".inp","r",stdin);
      |       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
pipes.cpp:101:14: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  101 |       freopen(task".out","w",stdout);
      |       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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