제출 #644230

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
644230		guagua0407	Valley (BOI19_valley)	C++17	23 / 100	159 ms	50028 KiB

valley

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#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);

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

const int mxn=1e5+5;
vector<pair<int,int>> adj[mxn];
pair<int,int> edgeid[mxn];
bool isshop[mxn]={false};
ll depth[mxn]={0},length[mxn]={0};
ll magic[mxn]={(ll)1e18};
ll jumping[20][mxn],jumpingans[20][mxn];
int st[mxn],en[mxn];
int parent[mxn];
int timer=0;

ll query(int top,int node){
    int x=node;
    int pathlength=depth[node]-depth[top];
    ll ans=magic[node];
    for(int i=0;i<20;i++){
        if(pathlength & (1<<i)){
            ans=min(ans,jumpingans[i][node]);
            node=jumping[i][node];
        }
    }
    return ans+length[x];
}

void dfs(int v,int p){
    st[v]=timer;
    timer++;
    parent[v]=p;
    for(auto u:adj[v]){
        if(u.f==p) continue;
        depth[u.f]=depth[v]+1;
        //cout<<v<<' '<<u.f<<' '<<u.s<<'\n';
        length[u.f]=length[v]+u.s;
        dfs(u.f,v);
    }
    en[v]=timer;
    timer++;
}

void dfs2(int v,int p){
    if(isshop[v]) magic[v]=length[v];
    else magic[v]=(ll)1e18;
    for(auto u:adj[v]){
        if(u.f==p) continue;
        dfs2(u.f,v);
        magic[v]=min(magic[v],magic[u.f]);
    }
}

int main() {_
	//setIO("wayne");
    int n,s,q,e;
    cin>>n>>s>>q>>e;
    for(int i=1;i<=n-1;i++){
        int a,b,w;
        cin>>a>>b>>w;
        adj[a].push_back({b,w});
        adj[b].push_back({a,w});
        edgeid[i]={a,b};
    }
    for(int i=0;i<s;i++){
        int x;
        cin>>x;
        isshop[x]=true;
    }
    dfs(e,0);
    dfs2(e,0);
    for(int i=1;i<=n;i++){
        magic[i]-=2*length[i];
    }
    for(int i=1;i<=n;i++){
        jumping[0][i]=parent[i];
        jumpingans[0][i]=magic[parent[i]];
    }
    for(int i=1;i<20;i++){
        for(int j=1;j<=n;j++){
            jumping[i][j]=jumping[i-1][jumping[i-1][j]];
            jumpingans[i][j]=min(jumpingans[i-1][j],jumpingans[i-1][jumping[i-1][j]]);
        }
    }
    /*for(int i=1;i<=n;i++){
        cout<<length[i]<<' ';
    }
    cout<<'\n';
    for(int i=1;i<=n;i++){
        cout<<magic[i]<<' ';
    }
    cout<<'\n';*/
    for(int i=0;i<q;i++){
        int edge,node;
        cin>>edge>>node;
        int top=(depth[edgeid[edge].f]>depth[edgeid[edge].s]?edgeid[edge].f:edgeid[edge].s);
        if(st[top]<=st[node] and en[node]<=en[top]){
            cout<<query(top,node)<<'\n';
        }
        else{
            cout<<"escaped"<<'\n';
        }
    }
	return 0;
}
//maybe its multiset not set

컴파일 시 표준 에러 (stderr) 메시지

valley.cpp: In function 'void setIO(std::string)':
valley.cpp:10:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |  freopen((s + ".in").c_str(), "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
valley.cpp:11:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |  freopen((s + ".out").c_str(), "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 27
• Subtask 3: 23 / 23
• Subtask 4: 0 / 41