Submission #957642

#	Time	Username	Problem	Language	Result	Execution time	Memory
957642		guagua0407	Synchronization (JOI13_synchronization)	C++17	0 / 100	143 ms	262144 KiB

synchronization

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

const int mxn=1e5+5;
vector<int> adj[mxn];
bitset<mxn> dp[mxn];
int depth[mxn];
bool ok[mxn];

void dfs(int v,int p=0){
    depth[v]=depth[p]+1;
    dp[v][v]=1;
    for(auto u:adj[v]){
        if(u==p) continue;
        dfs(u,v);
    }
}

int main() {_
    int n,m,q;
    cin>>n>>m>>q;
    vector<pair<int,int>> e(n-1);
    for(int i=0;i<n-1;i++){
        int a,b;
        cin>>a>>b;
        e[i]={a,b};
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    vector<int> qs;
    for(int i=0;i<m;i++){
        int x;
        cin>>x;
        x--;
        qs.push_back(x);
    }
    int root;
    cin>>root;
    dfs(root);
    for(auto x:qs){
        if(ok[x]){
            ok[x]=false;
            continue;
        }
        ok[x]=true;
        int a=e[x].f;
        int b=e[x].s;
        if(depth[a]>depth[b]) swap(a,b);
        dp[a]|=dp[b];
    }
    cout<<dp[root].count()<<'\n';
    return 0;
}
//maybe its multiset not set
//yeeorz
//laborz

Compilation message (stderr)

synchronization.cpp: In function 'void setIO(std::string)':
synchronization.cpp:15:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
synchronization.cpp:16:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 10
• Subtask 4: 0 / 20
• Subtask 5: 0 / 40