Submission #1096291

#	Time	Username	Problem	Language	Result	Execution time	Memory
1096291		TrinhKhanhDung	Valley (BOI19_valley)	C++14	100 / 100	248 ms	26520 KiB

valley

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(),v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define oo (ll)1e18
#define INF (ll)1e9
#define MOD (ll)(1e9 + 7)

using namespace std;

template<class T1, class T2>
    bool maximize(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}

template<class T1, class T2>
    bool minimize(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}

template<class T1, class T2>
    void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}

template<class T1, class T2>
    void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}

template<class T>
    void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}

struct seg{
    vector<ll> val, laz;
    int n;

    seg(int _n = 0){
        n = _n;
        val.resize(4 * n + 3, 0);
        laz.resize(4 * n + 3, 0);
    }

    void push(int i){
        ll t = laz[i];
        if(t == 0) return;
        laz[i] = 0;
        laz[i * 2] += t;
        laz[i * 2 + 1] += t;
        val[i * 2] += t;
        val[i * 2 + 1] += t;
    }

    void upd(int i, int l, int r, int u, int v, ll c){
        if(r < u || v < l) return;
        if(u <= l && r <= v){
            laz[i] += c;
            val[i] += c;
            return;
        }
        push(i);
        int m = (l + r) >> 1;
        upd(i * 2, l, m, u, v, c);
        upd(i * 2 + 1, m + 1, r, u, v, c);
        val[i] = min(val[i * 2], val[i * 2 + 1]);
    }

    ll get(int i, int l, int r, int u, int v){
        if(r < u || v < l) return oo;
        if(u <= l && r <= v) return val[i];
        push(i);
        int m = (l + r) >> 1;
        return min(get(i * 2, l, m, u, v), get(i * 2 + 1, m + 1, r, u, v));
    }
} it;

const int maxN = 1e5 + 10;

int N, M, Q, S;
vector<pair<int, int>> adj[maxN];
array<int, 3> edges[maxN];
int timer, nChain = 1;
int nChild[maxN], chain[maxN], topNode[maxN], par[maxN], in[maxN], out[maxN];
ll dist[maxN], ans[maxN];
vector<pair<int, int>> queries[maxN];

void countChild(int u, int p = -1){
    par[u] = p;
    nChild[u] = 1;
    for(auto o: adj[u]){
        int v = o.fi;
        int id = o.se;
        if(v == p) continue;
        countChild(v, u);
        nChild[u] += nChild[v];
        if(edges[id][0] == v) swap(edges[id][0], edges[id][1]);
    }
}

void hld(int u){
    if(topNode[nChain] == 0) topNode[nChain] = u;
    chain[u] = nChain;
    in[u] = ++timer;

    int heavyNode = -1;
    for(auto o: adj[u]){
        int v = o.fi;
        if(v == par[u]) continue;
        if(heavyNode == -1 || nChild[heavyNode] < nChild[v]){
            heavyNode = v;
        }
    }

    if(heavyNode != -1){
        hld(heavyNode);
    }

    for(auto o: adj[u]){
        int v = o.fi;
        if(v == par[u] || v == heavyNode) continue;
        nChain++;
        hld(v);
    }

    out[u] = timer;
}

void update(int a, int u, ll c){
    while(true){
        if(chain[u] == chain[a]){
            it.upd(1, 1, N, in[a], in[u], c);
            break;
        }
        int p = topNode[chain[u]];
        it.upd(1, 1, N, in[p], in[u], c);
        u = par[p];
    }
}

ll query(int a, int u){
    ll ans = oo;
    while(true){
        if(chain[u] == chain[a]){
            minimize(ans, it.get(1, 1, N, in[a], in[u]));
            break;
        }
        int p = topNode[chain[u]];
        minimize(ans, it.get(1, 1, N, in[p], in[u]));
        u = par[p];
    }
    return ans;
}

void calc(int u){
    for(auto o: queries[u]){
        int x = o.fi, id = o.se;
//        cout << u << ' ' << x << ' ' << o.se << '\n';
        if(!(in[x] <= in[u] && out[u] <= out[x])){
            ans[id] = -1;
            continue;
        }
        else{
            ans[id] = query(x, u);
        }
    }

    for(auto o: adj[u]){
        int v = o.fi;
        ll c = edges[o.se][2];
        if(v == par[u]) continue;
        update(S, u, c);
        calc(v);
        update(S, u, -c);
    }
}

void dfs(int u, int p = -1){
    for(auto o: adj[u]){
        int v = o.fi;
        ll c = edges[o.se][2];
        if(v == p) continue;
        dfs(v, u);
        minimize(dist[u], dist[v] + c);
    }
}

void solve(){
    cin >> N >> M >> Q >> S;
    for(int i = 1; i < N; i++){
        int u, v, c; cin >> u >> v >> c;
        adj[u].push_back({v, i});
        adj[v].push_back({u, i});
        edges[i] = {u, v, c};
    }
    memset(dist, 0x3f, sizeof dist);
    for(int i = 1; i <= M; i++){
        int x; cin >> x;
        dist[x] = 0;
    }

    countChild(S);
    hld(S);
    dfs(S);

    for(int i = 1; i <= Q; i++){
        int x, y; cin >> x >> y;
        x = edges[x][1];
        queries[y].push_back({x, i});
    }

    it = seg(N);

//    for(int i = 1; i < N; i++){
//        cout << edges[i][0] << ' ' << edges[i][1] << '\n';
//    }

    for(int i = 1; i <= N; i++){
        it.upd(1, 1, N, in[i], in[i], dist[i]);
    }

    calc(S);
    for(int i = 1; i <= Q; i++){
        if(ans[i] == -1){
            cout << "escaped\n";
        }
        else if(ans[i] >= oo){
            cout << "oo\n";
        }
        else{
            cout << ans[i] << '\n';
        }
    }
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
//     freopen("capsomayman.inp","r",stdin);
//     freopen("capsomayman.out","w",stdout);

    int t = 1;
//    cin >> t;
    while(t--){
        solve();
    }

    return 0;
}

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