Submission #413428

#	Time	Username	Problem	Language	Result	Execution time	Memory
413428		souvenir_vayne	Factories (JOI14_factories)	C++14	0 / 100	15 ms	12620 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, ll> pii;
 
const int MAXN = 5e5+5;
//int anc[MAXN][22];
int al[MAXN], pai[MAXN], sz[MAXN], used[MAXN];
ll h[MAXN], best[MAXN], dpai[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]) {
            dpai[i.f] = i.s;
            build(i.f, c);
        }
}
 
void dfs(int u, int p = -1) {
 
    for(pii &i : g[u])
        if(i.f != p) {
            al[i.f] = al[u] + 1;
            h[i.f] = h[u] + i.s;
            dfs(i.f, u);
        }
}
 
/*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;
    ll d = 0;
    while(u != -1) {
        best[u] = min(best[u], d);
        d += dpai[u];
        u = pai[u];
    }
}
 
ll query(int u) {
    int aux = u;
    ll ans = LINF, d = 0;
    while(u != -1) {
        ans = min(ans, best[u] + d);
        d += dpai[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;
    if(s <= t) {
        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]);
    }
    else {
        for(int i = 0; i < t; i++)
            update(y[i]);
        for(int i = 0; i < s; i++)
            ans = min(ans, query(x[i]));
        for(int i = 0; i < t; i++)
            reset(y[i]);
    }
    return ans;
}

Compilation message (stderr)

factories.cpp: In function 'void update(int)':
factories.cpp:80:9: warning: unused variable 'aux' [-Wunused-variable]
   80 |     int aux = u;
      |         ^~~
factories.cpp: In function 'long long int query(int)':
factories.cpp:90:9: warning: unused variable 'aux' [-Wunused-variable]
   90 |     int aux = u;
      |         ^~~

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