Submission #1110048

#	Time	Username	Problem	Language	Result	Execution time	Memory
1110048		Icelast	Valley (BOI19_valley)	C++17	100 / 100	355 ms	42028 KiB

valley

#include <iostream>
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll maxn = 2*1e5+5, INF = 1e18+9;
template<class Info, class Tag>
struct LazySegmentTree {
    int n;
    vector<Info> info;
    vector<Tag> tag;
    LazySegmentTree() : n(0) {}
    LazySegmentTree(int n_, Info v_ = Info()) {
        init(n_, v_);
    }
    template<class T>
    LazySegmentTree(vector<T> init_) {
        init(init_);
    }
    void init(int n_, Info v_ = Info()) {
        init(vector<Info>(n_, v_));
    }
    template<class T>
    void init(vector<T> init_) {
        n = init_.size();
        info.assign(4 << __lg(n), Info());
        tag.assign(4 << __lg(n), Tag());
        function<void(int, int, int)> build = [&](int p, int l, int r) {
            if (r - l == 1) {
                info[p] = init_[l];
                return;
            }
            int m = (l + r) / 2;
            build(2 * p, l, m);
            build(2 * p + 1, m, r);
            pull(p);
        };
        build(1, 0, n);
    }
    void pull(int p) {
        info[p] = info[2 * p] + info[2 * p + 1];
    }
    void apply(int p, const Tag &v) {
        info[p].apply(v);
        tag[p].apply(v);
    }
    void push(int p) {
        apply(2 * p, tag[p]);
        apply(2 * p + 1, tag[p]);
        tag[p] = Tag();
    }
    void modify(int p, int l, int r, int x, const Info &v) {
        if (r - l == 1) {
            info[p] = v;
            return;
        }
        int m = (l + r) / 2;
        push(p);
        if (x < m) {
            modify(2 * p, l, m, x, v);
        } else {
            modify(2 * p + 1, m, r, x, v);
        }
        pull(p);
    }
    void modify(int p, const Info &v) {
        modify(1, 0, n, p, v);
    }
    Info rangeQuery(int p, int l, int r, int x, int y) {
        if (l >= y || r <= x) {
            return Info();
        }
        if (l >= x && r <= y) {
            return info[p];
        }
        int m = (l + r) / 2;
        push(p);
        return rangeQuery(2 * p, l, m, x, y) + rangeQuery(2 * p + 1, m, r, x, y);
    }
    Info rangeQuery(int l, int r) {
        return rangeQuery(1, 0, n, l, r);
    }
    void rangeApply(int p, int l, int r, int x, int y, const Tag &v) {
        if (l >= y || r <= x) {
            return;
        }
        if (l >= x && r <= y) {
            apply(p, v);
            return;
        }
        int m = (l + r) / 2;
        push(p);
        rangeApply(2 * p, l, m, x, y, v);
        rangeApply(2 * p + 1, m, r, x, y, v);
        pull(p);
    }
    void rangeApply(int l, int r, const Tag &v) {
        return rangeApply(1, 0, n, l, r, v);
    }
    template<class F>
    int findFirst(int p, int l, int r, int x, int y, F &&pred) {
        if (l >= y || r <= x) {
            return -1;
        }
        if (l >= x && r <= y && !pred(info[p])) {
            return -1;
        }
        if (r - l == 1) {
            return l;
        }
        int m = (l + r) / 2;
        push(p);
        int res = findFirst(2 * p, l, m, x, y, pred);
        if (res == -1) {
            res = findFirst(2 * p + 1, m, r, x, y, pred);
        }
        return res;
    }
    template<class F>
    int findFirst(int l, int r, F &&pred) {
        return findFirst(1, 0, n, l, r, pred);
    }
    template<class F>
    int findLast(int p, int l, int r, int x, int y, F &&pred) {
        if (l >= y || r <= x) {
            return -1;
        }
        if (l >= x && r <= y && !pred(info[p])) {
            return -1;
        }
        if (r - l == 1) {
            return l;
        }
        int m = (l + r) / 2;
        push(p);
        int res = findLast(2 * p + 1, m, r, x, y, pred);
        if (res == -1) {
            res = findLast(2 * p, l, m, x, y, pred);
        }
        return res;
    }
    template<class F>
    int findLast(int l, int r, F &&pred) {
        return findLast(1, 0, n, l, r, pred);
    }
};

struct Tag {
    ll add = 0;
    void apply(const Tag &t) & {
        add += t.add;
    }
};

struct Info {
    ll mn = INF;
    void apply(const Tag &t) & {
        mn += t.add;
    }
    Info operator+(const Info &b) {
        return {min(mn, b.mn)};
    }
};
struct edge{
    ll u, v, w;
};
struct que{
    int I, R, id;
};
void solve(){
    int n, S, Q, H;
    cin >> n >> S >> Q >> H;
    vector<vector<pair<ll, ll>>> adj(n+1);
    vector<edge> e(n);
    for(int i = 1; i < n; i++){
        ll u, v, w;
        cin >> u >> v >> w;
        adj[u].push_back({v, w});
        adj[v].push_back({u, w});
        e[i] = {u, v, w};
    }
    vector<bool> is_special(n+1, false);
    for(int i = 1; i <= S; i++){
        int x;
        cin >> x;
        is_special[x] = true;
    }
    vector<que> q(Q+1);
    for(int i = 1; i <= Q; i++){
        cin >> q[i].I >> q[i].R;
        q[i].id = i;
    }
    int timer = 0;
    vector<int> rt(n+1), lt(n+1);
    vector<ll> f(n+1, INF);
    vector<int> depth(n+1, -1);
    auto root_tree = [&](auto root_tree, int u, int p, ll len) -> void{
        timer ++;
        lt[u] = timer;
        depth[u] = depth[p]+1;
        if(is_special[u]){
            f[u] = len;
        }else{
            f[u] = INF;
        }
        for(auto it : adj[u]){
            int v = it.first;
            ll w = it.second;
            if(v == p) continue;
            root_tree(root_tree, v, u, len+w);
        }
        rt[u] = timer;
    };
    root_tree(root_tree, H, 0, 0);
    for(int i = 1; i < n; i++){
        if(depth[e[i].u] > depth[e[i].v]){
            swap(e[i].u, e[i].v);
        }
    }
    vector<vector<que>> b(n+1);
    for(int i = 1; i <= Q; i++){
        b[q[i].R].push_back(q[i]);
    }
    LazySegmentTree<Info, Tag> T(n+1);
    for(int i = 1; i <= n; i++){
        T.modify(lt[i], {f[i]});
    }
    vector<ll> ans(Q+1, -3);
    auto is_anc = [&](int u, int v) -> bool{
        return lt[u] <= lt[v] && lt[v] <= rt[u];
    };
    for(int i = 1; i <= Q; i++){
        int v = e[q[i].I].v;
        if(!is_anc(v, q[i].R)){
            ans[i] = -2;
        }
    }
    auto dfs = [&](auto dfs, int u, int p) -> void{
        for(auto it : b[u]){
            ll res = INF;
            int id = it.id;
            if(ans[id] == -2) continue;
            int v = e[it.I].v;
            if(is_anc(v, u)){
                res = T.rangeQuery(lt[v], rt[v]+1).mn;
            }else{
                res = min(T.rangeQuery(1, lt[v]).mn, T.rangeQuery(rt[v]+1, n+1).mn);
            }
            if(res >= 1e15){
                ans[id] = -1;
            }else{
                ans[id] = res;
            }
        }
        for(auto it : adj[u]){
            int v = it.first;
            ll w = it.second;
            if(v == p) continue;
            ll prv_fu, prv_fv, fu, fv;
            T.rangeApply(1, lt[v], {w});
            T.rangeApply(rt[v]+1, n+1, {w});
            T.rangeApply(lt[v], rt[v]+1, {-w});

            dfs(dfs, v, u);

            T.rangeApply(1, lt[v], {-w});
            T.rangeApply(rt[v]+1, n+1, {-w});
            T.rangeApply(lt[v], rt[v]+1, {w});
        }
    };
    dfs(dfs, H, 0);
    for(int i = 1; i <= Q; i++){
        if(ans[i] == -2){
            cout << "escaped";
        }
        if(ans[i] == -1){
            cout << "oo";
        }
        if(ans[i] >= 0){
            cout << ans[i];
        }
        cout << "\n";
    }
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    solve();
}

Compilation message (stderr)

valley.cpp: In instantiation of 'solve()::<lambda(auto:24, int, int)> [with auto:24 = solve()::<lambda(auto:24, int, int)>]':
valley.cpp:270:18:   required from here
valley.cpp:258:16: warning: unused variable 'prv_fu' [-Wunused-variable]
  258 |             ll prv_fu, prv_fv, fu, fv;
      |                ^~~~~~
valley.cpp:258:24: warning: unused variable 'prv_fv' [-Wunused-variable]
  258 |             ll prv_fu, prv_fv, fu, fv;
      |                        ^~~~~~
valley.cpp:258:32: warning: unused variable 'fu' [-Wunused-variable]
  258 |             ll prv_fu, prv_fv, fu, fv;
      |                                ^~
valley.cpp:258:36: warning: unused variable 'fv' [-Wunused-variable]
  258 |             ll prv_fu, prv_fv, fu, fv;
      |                                    ^~

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