Submission #413414

#	Time	Username	Problem	Language	Result	Execution time	Memory
413414		souvenir_vayne	Factories (JOI14_factories)	C++14	15 / 100	8013 ms	172116 KiB

factories

#include <bits/stdc++.h>
#include "factories.h"
#define pb push_back
#define LINF 0x3f3f3f3f3f3f3f3f
#define endl '\n'
#define ll long long
#define f first
#define s second
using namespace std;
typedef pair<int, int> pii;

const int MAXN = 5e5+5;
ll anc[MAXN][22], al[MAXN], h[MAXN], pai[MAXN], sz[MAXN], used[MAXN], best[MAXN];
vector<pii> g[MAXN];

ll getsz(int u, int p) {
    sz[u] = 1;
    for(pii &i : g[u])
        if(i.f != p && !used[i.f])
            sz[u] += getsz(i.f, u);
    return sz[u];
}

ll findc(int u, int p, int n) {
    for(pii &i : g[u])
        if(i.f != p && !used[i.f] && sz[i.f] > n/2)
            return findc(i.f, u, n);
    return u;
}

void build(int u, int p) {
    int c = findc(u, -1, getsz(u, -1));
    used[c] = 1;
    pai[c] = p;

    for(pii &i : g[c])
        if(!used[i.f])
            build(i.f, c);
}

void dfs(int u) {

    for(pii &i : g[u])
        if(i.f != anc[u][0]) {
            anc[i.f][0] = u;
            al[i.f] = al[u] + 1;
            h[i.f] = h[u] + i.s;
            dfs(i.f);
        }
}

int getlca(int a, int b) {
    if(al[a] < al[b])
        swap(a, b);
    for(int i = 0; i <= 20; i++)
        if( (1<<i) & (al[b] - al[a]) )
            a = anc[a][i];

    if(a == b)
        return a;

    for(int i = 20; i >= 0; i--)
        if(anc[a][i] != anc[b][i])
            a = anc[a][i], b = anc[b][i];

    return anc[a][0];

}

ll dist(int a, int b) {
    return h[a] + h[b] - 2*h[getlca(a, b)];
}

void update(int u) {
    int aux = u;
    while(u != -1) {
        best[u] = min(best[u], dist(aux, u));
        //debug2(u, best[u]);
        u = pai[u];
    }
}

ll query(int u) {
    ll aux = u, ans = LINF;
    while(u != -1) {
        ans = min(ans, best[u] + dist(aux, u));
        u = pai[u];
    }
    return ans;
}

void reset(int u) {
    while(u != -1) {
        best[u] = LINF;
        u = pai[u];
    }
}

void Init(int n, int a[], int b[], int c[]) {
    for(int i = 0; i < n; i++)
        best[i] = LINF;

    for(int i = 0; i < n-1; i++) {
        g[a[i]].pb({b[i], c[i]});
        g[b[i]].pb({a[i], c[i]});
    }

    dfs(0);
    for(int j = 1; j < 22; j++)
        for(int i = 1; i <= n; i++)
            anc[i][j] = anc[anc[i][j-1]][j-1];
    build(0, -1);
}

ll Query(int s, int x[], int t, int y[]) {

    ll ans = LINF;
    for(int i = 0; i < s; i++)
        update(x[i]);
    for(int i = 0; i < t; i++)
        ans = min(ans, query(y[i]));
    for(int i = 0; i < s; i++)
        reset(x[i]);
    return ans;
}

• Subtask 1: 15 / 15
• Subtask 2: 0 / 18
• Subtask 3: 0 / 67