Submission #123248

#	Time	Username	Problem	Language	Result	Execution time	Memory
123248		miguel	Valley (BOI19_valley)	C++14	59 / 100	438 ms	25828 KiB

valley

#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
using namespace std;
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define dbg(x) cout << #x << '=' << x << '\n';
#define ll long long
#define sz size()
#define x first
#define y second
#define pi pair <int, int>
#define pii pair <pi, int>
#define vi vector <int>
const ll mod = 1000000007;
#define int ll
int n, s, q, e;
vector<int> d;
int f[100001], l[100001];
pi road[100001];
int dt[1001];
bitset<100001> sh;
vector <pi> g[100001];

void dfs(int p, int cur){
    d.pb(cur);
    for(pi i: g[cur]){
        if(i.x!=p) dfs(cur, i.x);
    }
    d.pb(cur);
}

void bfs(int rip1, int rip2, int p, int cur){
    for(pi i: g[cur]){
        if(i.x!=p && (min(cur, i.x)!=rip1 || max(cur, i.x)!=rip2)){
            dt[i.x]=dt[cur]+i.y;
            bfs(rip1, rip2, cur, i.x);
        }
    }
}

int32_t main(){
    ios_base :: sync_with_stdio(0); cin.tie(); cout.tie();
    cin>>n>>s>>q>>e;
    for(int i=1; i<=n-1; i++){
        int x, y, z;
        cin>>x>>y>>z;
        road[i]={x, y};
        g[x].pb({y, z});
        g[y].pb({x, z});
    }
    for(int i=1; i<=s; i++){
        int x;
        cin>>x;
        sh[x]=1;
    }
    dfs(0, e);
    for(int i=0; i<d.size(); i++){
        l[d[i]]=i+1;
        if(!f[d[i]]) f[d[i]]=i+1;
    }
    if(s==n){
        //for(int i=1; i<=n; i++){cout<<i<<" "<<f[i]<<" "<<l[i]<<endl;}
        for(int i=1; i<=q; i++){
            int rd, r;
            cin>>rd>>r;
            int x=road[rd].x, y=road[rd].y;
            if(f[x]<=f[r] && l[x]>=l[r] && f[y]<=f[r] && l[y]>=l[r]) cout<<0<<"\n";
            else cout<<"escaped\n";
        }
        return 0;
    }
    for(int i=1; i<=q; i++){
        int rd, r;
        cin>>rd>>r;
        int x=road[rd].x, y=road[rd].y;
        if(x>y) swap(x, y);
        if(f[x]<=f[r] && l[x]>=l[r] && f[y]<=f[r] && l[y]>=l[r]){
            for(int j=1; j<=n; j++) dt[j]=1e18;
            dt[r]=0;
            bfs(x, y, 0, r);
            int ans=1e18;
            for(int i=1; i<=n; i++){
                if(sh[i]) ans=min(ans, dt[i]);
            }
            if(ans!=1e18) cout<<ans<<"\n";
            else cout<<"oo\n";
        }
        else cout<<"escaped\n";
    }
}

Compilation message (stderr)

valley.cpp: In function 'int32_t main()':
valley.cpp:57:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<d.size(); i++){
                  ~^~~~~~~~~

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