Submission #31083

#	Time	Username	Problem	Language	Result	Execution time	Memory
31083		WhipppedCream	Race (IOI11_race)	C++14	100 / 100	1327 ms	38380 KiB

race

#include <bits/stdc++.h>
#include "race.h"
#define ii pair<int, int>
#define X first
#define Y second
#define pb push_back
#define vi vector<int>
#define vii vector< pair<int, int> >
#define iii pair< ii, int >
typedef long long ll;
using namespace std;
vector< ii > adj[200005];
int use[200005];
int deg[200005];
int maxnow[200005];
int mic[200005];
void memsetNode(int u, int par)
{
    mic[u] = -1;
    maxnow[u] = 0;
    //printf("set 0 at %d\n", u);
    for(int i = 0; i< (int) adj[u].size(); i++)
    {
        int v = adj[u][i].X;
        if(use[v]) continue;
        if(v == par) continue;
        memsetNode(v, u);
    }
}
int cnt(int u, int par)
{
    if(mic[u] != -1) return mic[u];
    int sum = 1;
    for(int i = 0; i< (int) adj[u].size(); i++)
    {
        int v = adj[u][i].X;
        if(use[v]) continue;
        if(v == par) continue;
        sum += cnt(v, u);
    }
    //printf("computed %d %d\n", u, par);
    return mic[u] = sum;
}
void update(int u, int par, int book)
{
    //printf("update %d %d %d\n", u, par, book);
    maxnow[u] = max(maxnow[u], book);
    int sm = 1;
    for(int i = 0; i< (int) adj[u].size(); i++)
    {
        ii k = adj[u][i];
        if(k.X == par) continue;
        if(use[k.X]) continue;
        maxnow[k.X] = max(maxnow[k.X], 1+book);
        maxnow[u] = max(maxnow[u], cnt(k.X, u));
        //printf("added (%d, %d)", k.X, u);
        sm += cnt(k.X, u);
    }
    sm += book;
    //printf("sm is %d for %d\n", sm, u);
    for(int i = 0; i< (int) adj[u].size(); i++)
    {
        ii k = adj[u][i];
        if(k.X == par) continue;
        if(use[k.X]) continue;
        update(k.X, u, sm - cnt(k.X, u));
    }
}
int findBest(int u, int par)
{
    int best = -1;
    //printf("%d: %d\n", u, maxnow[u]);
    for(int i = 0; i< (int) adj[u].size(); i++)
    {
        int v = adj[u][i].X;
        if(use[v]) continue;
        if(v == par) continue;
        int here = findBest(v, u);
        if(best == -1 || maxnow[here]< maxnow[best]) best = here;
    }
    int res;
    if(best == -1) res = u;
    else if(maxnow[best]< maxnow[u]) res = best;
    else res = u;
    //printf("of size %d\n", maxnow[res]);
    return res;
}
int memsetcnt = 0;
void findNode(int u, int par)
{
    //printf("its me\n");
    int st = u;
    //printf("--------memsetting %d %d\n", u, par);
    memsetcnt++;
    //if(memsetcnt % 10000 == 0) printf("%d\n", memsetcnt/1000);
    memsetNode(u, par);
    update(st, par, 0);
    //printf("kuy\n");
}
int bestPath[1000005];
vii joe;
void diep(int u, int par, int dist, int len)
{
    if(dist > 1000000) return;
    joe.pb(ii(dist, len));
    //printf("%d %d %d %d\n", u, par, dist, len);
    for(int i = 0; i< (int) adj[u].size(); i++)
    {
        int v = adj[u][i].X;
        int w = adj[u][i].Y;
        if(v == par) continue;
        if(use[v]) continue;
        diep(v, u, dist+w, len+1);
    }
}
int k;
int n;
int solve(int u, int par)
{
    //memset maxnow 0
    //memset mic
    //printf("hello\n");
    findNode(u, par);
    int root = findBest(u, par);
    //printf("--------------root is %d\n", root);
    vector<int> Set;
    int best = 1e9;
    bestPath[0] = 0;
    for(int i = 0; i< (int) adj[root].size(); i++)
    {
        joe.clear();
        int v = adj[root][i].X;
        if(v == par) continue;
        if(use[v]) continue;
        diep(v, root, adj[root][i].Y, 1);
        for(int j = 0; j< (int) joe.size(); j++)
        {
            Set.pb(joe[j].X);
            if(k-joe[j].X >= 0 && bestPath[k-joe[j].X] != -1)
            {
                best = min(best, bestPath[k-joe[j].X] + joe[j].Y);
            }
        }
        for(int j = 0; j< (int) joe.size(); j++)
        {
            if(bestPath[joe[j].X] == -1 || bestPath[joe[j].X] > joe[j].Y) bestPath[joe[j].X] = joe[j].Y;
            //lprintf("%d\n", joe[j].X);
        }
    }
    use[root] = 1;
    for(int i = 0; i< (int) Set.size(); i++)
    {
        bestPath[Set[i]] = -1;
    }
    for(int i = 0; i< (int) adj[root].size(); i++)
    {
        int v = adj[root][i].X;
        if(v == par) continue;
        if(use[v]) continue;
        best = min(best, solve(v, root));
    }
    return best;
}
int best_path(int N, int K, int H[][2], int L[])
{
    memset(bestPath, -1, sizeof bestPath);
    memset(mic, -1, sizeof mic);
    //freopen("grader.in.16", "r", stdin);
	n = N; k = K;
    for(int i = 0; i< n-1; i++)
    {
        int a, b, w;
		a = H[i][0], b = H[i][1], w = L[i];
        adj[a].pb(ii(b, w));
        adj[b].pb(ii(a, w));
        deg[a]++; deg[b]++;
    }
    int res = solve(0, -1);
    if(res == 1e9) return -1;
    return res;
	return 0;
}

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 22 / 22
• Subtask 4: 57 / 57