Submission #1104626

#	Time	Username	Problem	Language	Result	Execution time	Memory
1104626		LTTrungCHL	Valley (BOI19_valley)	C++17	100 / 100	313 ms	98816 KiB

valley

///***LTT***///
/// ->NHAT QUOC GIA<- ///
#include<bits/stdc++.h>
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("popcnt")
#define int long long
#define endl "\n"
#define F first
#define S second
#define pb push_back
using namespace std;
const long long oo = 1e9+7;
const int N = 1e5 + 5;
int L[N], R[N], trace[N];
long long dis[N], tree[N * 4], lazy[N * 4];
int cnt[N];
queue <int> qu[N];
vector <pair <int, long long>> adj[N];
bool dd[N];
int l1[N], l2[N], r1[N], r2[N];
int n, e, s;
long long ans[N];
int q, a[N], b[N], w;
int tt = 0;
void build(int id,int l,int r){
    if (l == r){
        if (dd[trace[l]]) tree[id] = dis[trace[l]]; else tree[id] = 1e18;
        return;
    }
    int mid = (l + r)/2;
    build(id * 2, l, mid);
    build(id * 2 + 1, mid + 1, r);
    tree[id] = min(tree[id  * 2], tree[id * 2 + 1]);
    return;
}
void dfs1(int u,int p,long long d){
    L[u] = ++tt;
    dis[u] = d;
    if (dd[u]) cnt[u]++;
    trace[tt] = u;
    for (auto x : adj[u]){
        if (x.F != p){
            dfs1(x.F, u, 1ll * d + x.S);
            cnt[u] += cnt[x.F];
        }
    }
    R[u] = tt;
    return;
}
void down(int id,int l,int r){
    if (l != r){
        tree[id * 2] += lazy[id];
        tree[id * 2 + 1] += lazy[id];
        lazy[id * 2] += lazy[id];
        lazy[id * 2 + 1] += lazy[id];
    }
    lazy[id] = 0;
    return;
}
void update(int id,int l,int r,int u,int v,long long val){
    if (lazy[id] != 0) down(id,l,r);
    if (l > v or r < u) return;
    if (l >= u and r <= v){
        tree[id] += val;
        lazy[id] += val;
        return;
    }
    int mid = (l + r)/2;
    update(id*2,l,mid,u,v,val);
    update(id*2 + 1,mid + 1,r,u,v,val);
    tree[id] = min(tree[id * 2], tree[id * 2 + 1]);
}
long long get(int id,int l,int r,int u,int v){
    if (lazy[id] != 0) down(id,l,r);
    if (l > v or r < u) return oo  * oo;
    if (l >= u and r <= v) return tree[id];
    int mid = (l + r)/2;
    return min(get(id * 2,l, mid,u ,v), get(id * 2 + 1,mid + 1, r, u, v));
}
void dfs(int u,int p, long long c){
    update(1,1,n,L[u],R[u], -c);
    if (L[u] - 1 != 0)
        update(1,1,n,1,L[u] - 1, c);
    if (R[u] + 1 <= n)
        update(1,1,n,R[u] + 1, n, c);
    while (!qu[u].empty()){
        int tt = qu[u].front();
        qu[u].pop();
        if (l2[tt] == 0){
            ans[tt] = get(1,1,n,l1[tt], r1[tt]);
        } else {
            long long v1 = get(1,1,n,l1[tt],r1[tt]);
            long long v2 = oo * oo;
            if (l2[tt] <= r2[tt]){
                v2 = get(1,1,n,l2[tt], r2[tt]);
            }
            ans[tt] = min(v1, v2 );
        }
    }
    for (auto x : adj[u]){
        if (x.F != p){
            dfs(x.F, u, x.S);
        }
    }
    update(1,1,n,L[u],R[u], c);
    if (L[u] - 1 != 0)
        update(1,1,n,1,L[u] - 1, -c);
    if (R[u] + 1 <= n)
        update(1,1,n,R[u] + 1, n, -c);
    return;
}
void inp(){
    cin >> n >> s >> q >> e;
    for (int i = 1;i < n;i++){
        cin >> a[i] >> b[i] >> w;
        adj[a[i]].pb({b[i],w});
        adj[b[i]].pb({a[i],w});
    }
    return;
}
void solve(){
    for (int i = 1;i <= s;i++){
        int u;
        cin >> u;
        dd[u] = true;
    }
    dfs1(1,0, 0);
    build(1,1,n);
    int tt, r;
//    cout << L[e] <<" "<< R[e] <<"\n";
    for (int i = 1;i <= q;i++){
        cin >> tt >> r;
        int u = a[tt];
        int v = b[tt];
        if (L[u] > L[v]) swap(u,v);
        if (L[r] >= L[v] and L[r] <= R[v]){
            l1[i] = L[v];
            r1[i] = R[v];
            if (L[e] >= L[v] and L[e] <= R[v]){
                ans[i] = -1;
                continue;
            }
            if (cnt[v] == 0) ans[i] = -2; else qu[r].push(i);
        } else {
            l1[i] = 1;
            r1[i] = L[v] - 1;
            l2[i] = R[v] + 1;
            r2[i] = n;
            if (L[e] < L[v] or L[e] > R[v]){
                ans[i] = -1;
                continue;
            }
            if (cnt[1] - cnt[v] == 0) ans[i] = -2; else qu[r].push(i);
        }
    }
    dfs(1,0, 0);
    for (int i = 1;i <= q;i++){
        if (ans[i] == -1){
            cout <<"escaped\n";
            continue;
        }
        if (ans[i] == -2){
            cout << "oo\n";
            continue;
        }
        cout << ans[i] <<"\n";
    }
    return;
}
signed main(){
    ios_base::sync_with_stdio(NULL);
    cin.tie(NULL);
    cout.tie(NULL);
//    if (fopen("file.inp", "r")){
//        freopen("VALLEY.inp", "r", stdin);
//        freopen("VALLEY.out", "w", stdout);
//    }
    //int t;
    //cin >> t;
    //while(t--){
    inp();
    solve();
    //}
}

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