# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
413403 | souvenir_vayne | Factories (JOI14_factories) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#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
typedef pair<int, int> pii;
using namespace std;
const int MAXN = 5e5+5;
int anc[MAXN][22], al[MAXN], h[MAXN], pai[MAXN], sz[MAXN], used[MAXN], best[MAXN];
vector<pii> g[MAXN];
int 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];
}
int 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];
}
int 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];
}
}
int query(int u) {
int 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);
}
long long Query(int s, int x[], int t, int y[]) {
int 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;
}