Submission #795921

#	Time	Username	Problem	Language	Result	Execution time	Memory
795921		TB_	Valley (BOI19_valley)	C++17	100 / 100	256 ms	54876 KiB

valley

#include <bits/stdc++.h>
using namespace std;

// #undef _GLIBCXX_DEBUG                // disable run-time bound checking, etc
// #pragma GCC optimize("Ofast,inline") // Ofast = O3,fast-math,allow-store-data-races,no-protect-parens
// #pragma GCC optimize ("unroll-loops")

// #pragma GCC target("bmi,bmi2,lzcnt,popcnt")                      // bit manipulation
// #pragma GCC target("movbe")                                      // byte swap
// #pragma GCC target("aes,pclmul,rdrnd")                           // encryption
// #pragma GCC target("avx,avx2,f16c,fma,sse3,ssse3,sse4.1,sse4.2") // SIMD

// #include <bits/extc++.h>
// using namespace __gnu_pbds;
// template<class T>using ordered_set = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
// template<class T>using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define ll long long
#define INF (ll)1e9+7
#define fo(i, n) for(int i=0;i<((ll)n);i++)
#define deb(x) cout << #x << " = " << x << endl;
#define deb2(x, y) cout << #x << " = " << x << ", " << #y << " = " << y << endl
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define LSOne(S) ((S) & (-S))
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
inline int readint(){ int v = 0; char c; while((c = getchar()) != EOF && c != ' ' && c != '\n'){ v *= 10; v += c - '0'; } return v; }
inline int readintsigned() { int v = 0; int sign = 1; char c = getchar(); if (c == '-') { sign = -1; } else { v += c - '0'; } while ((c = getchar()) != EOF && c != ' ' && c != '\n') { v *= 10; v += c - '0'; } return v * sign; }
inline string readstring() { string s; char c; while ((c = getchar()) != EOF && c != '\n' && c != ' ') { s.push_back(c); } return s; }
template <class result_t=std::chrono::milliseconds,class clock_t=std::chrono::steady_clock,class duration_t = std::chrono::milliseconds>
auto since(std::chrono::time_point<clock_t, duration_t> const& start){return std::chrono::duration_cast<result_t>(clock_t::now() - start);}
typedef pair<int, int> pii;
typedef pair<ll, ll> pl;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpii;
typedef vector<pl> vpl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<vpii> vvpii;
typedef vector<vpl> vvpl;

vl toStore;
vvpl adj(100001);
vpl paths;

vl closestShop(100001, 1e18);
vvl bl(100001, vl(24, -1));
vl v(100001);

int sIndex = 0;


ll lengthTo[100001];
int depth[100001];
int siz[100001];
int segIndex[100001];
int heavyChild[100001];
int heavyParent[100001];

int dfs(int u, int d, int last){ // siz, toShop
    bl[u][0] = last;
    depth[u] = d;
    siz[u] = 1;
    int t_heavyestChild = -1;
    for(auto &[v, w] : adj[u]){
        if(v == last) continue;
        siz[u] += dfs(v, d+1, u); 
        closestShop[u] = min(closestShop[u], closestShop[v]+w);
        if(siz[v] > t_heavyestChild){
            t_heavyestChild = siz[v];
            heavyChild[u] = v;
        }
    }
    return siz[u];
}

void dfs2(int u, int last = -1, int heavyPar = -1){
    if(heavyPar == -1) heavyPar = u;
    heavyParent[u] = heavyPar;
    v[sIndex] = closestShop[u];
    segIndex[u] = sIndex++;

    if(heavyChild[u] != -1) dfs2(heavyChild[u], u, heavyPar);


    for(auto &[v, w] : adj[u]){
        if(v == last || heavyChild[u] == v) continue;
        dfs2(v, u);
    }
}

void dfs3(int u, int last = -1, ll dis = 0){
    lengthTo[segIndex[u]] = dis;
    for(auto &[v, w] : adj[u]){
        if(v == last) continue;
        dfs3(v, u, dis-w);
    }
}

struct Node{
    Node *lnode, *rnode;
    int l, r;
    ll val;
    Node(int l, int r) : l(l), r(r){
        if(r-l == 1) {
            val = v[l]+lengthTo[l];
        }
        else{
            int mid = (l + r) / 2;
            lnode = new Node(l, mid);
            rnode = new Node(mid, r);
            val = min(lnode->val, rnode->val);
        }
    }

    ll query(int lo, int hi){
        if(hi <= l || r <= lo) return 1e18;
        if(lo <= l && r <= hi) return val;
        return min(lnode->query(lo, hi), rnode->query(lo, hi));
    }

};


int main() {
    // cout << fixed << setprecision(20);
    // auto start = std::chrono::steady_clock::now(); // since(start).count()
    cin.tie(0)->sync_with_stdio(0);

    ll n, s, q, e, from, to, val, closed, start;

    cin >> n >> s >> q >> e;

    fo(i, n-1){
        cin >> from >> to >> val;
        adj[--from].pb({--to, val});
        adj[to].pb({from, val});
        paths.pb({from, to});
    }
    fo(i, s){
        cin >> val;
        closestShop[val-1] = 0;
    }

    memset(depth, 0, sizeof(depth));
    memset(siz, 0, sizeof(siz));
    memset(segIndex, 0, sizeof(segIndex));
    memset(heavyChild, -1, sizeof(heavyChild));
    memset(heavyParent, 0, sizeof(heavyParent));
    memset(lengthTo, 0, sizeof(lengthTo));
    e--;
    dfs(e, 0, e);
    dfs2(e);
    dfs3(e);

    fo(i, 22){
        fo(j, n)
            bl[j][i+1] = bl[bl[j][i]][i]; 
    }

    Node st(0, n);

    fo(x, q){
        cin >> closed >> start; 
        pl path = paths[closed-1];
        start--;
        int closedNode = (depth[path.F] < depth[path.S] ? path.S : path.F);
        if(depth[start] >= depth[closedNode]){
            int tempNode = start;
            for(int mask = depth[start]-depth[closedNode];mask;mask-=LSOne(mask)){
                tempNode = bl[tempNode][__builtin_ctz(LSOne(mask))];
            }
            if(tempNode == closedNode){
                tempNode = start;
                ll res = 1e18;
                while(depth[tempNode] >= depth[closedNode]){
                    int nextNode = heavyParent[tempNode];
                    res = min(res, st.query(segIndex[nextNode]+max(0, depth[closedNode]-depth[nextNode]), segIndex[tempNode]+1));
                    if(depth[tempNode] == 0) break;
                    tempNode = bl[nextNode][0];
                }
                res -= lengthTo[segIndex[start]];
                cout << (res>1e17?"oo":to_string(res)) << "\n";
                continue;
            }
        }
        cout << "escaped\n";
    }

    return 0;
}

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