Submission #1112058

#	Time	Username	Problem	Language	Result	Execution time	Memory
1112058		FucKanh	Race (IOI11_race)	C++14	21 / 100	128 ms	72008 KiB

race

#include <bits/stdc++.h>
#include <race.h>
#define ll long long
#define pii pair<long long,long long>

using namespace std;

const ll maxn = 5e5 + 2;

ll sz[maxn],h[maxn],k;
vector<pii> a[maxn];
ll ans = LLONG_MAX;
map<ll,ll> mp[maxn];

void dfs(ll u, ll w, ll pa) {
    assert(h[u]!=0);
    for (pii tmp : a[u]) {
        ll wv,v; tie(v,wv) = tmp;
        if (v==pa) continue;
        h[v] = h[u] + 1;
        dfs(v,w+wv,u);

        mp[v][w+wv] = h[v];

        if (mp[u].size() < mp[v].size()) swap(mp[u],mp[v]);

        for (pii val : mp[v]) {
            if (val.second==0) continue;
            if (val.first - w < k && mp[u][k-val.first+2*w] != 0) {
                ans = min(ans, mp[u][k-val.first+2*w] - h[u] + val.second - h[u]);
            }
        }

        mp[u].insert(mp[v].begin(),mp[v].end());
        if (mp[u][w + k] != 0) {
            ans = min(ans, mp[u][w+k]-h[u]);
        }
    }

}

int best_path(int _n, int _k, int _h[][2], int _L[])
{
    k = _k;
    for (ll i = 0; i < _n - 1; i++){
        ll x = _h[i][0], y = _h[i][1];
        ll w = _L[i];
        a[x].push_back({y,w});
        a[y].push_back({x,w});
    }
    h[0] = 1;
    dfs(0,0,-1);
    assert(ans > 0);
    return ans == LLONG_MAX ? -1 : ans;
}

//signed main() {
//    int N = 11, K = 12;
//    int H[10][2] = {
//    {0,1},
//    {0,2},
//    {0,8},
//    {1,3},
//    {3,7},
//    {2,4},
//    {0,5},
//    {5,6},
//    {8,9},
//    {9,10},
//    };
//    int L[10] = {1,1,1,2,3,2,1,2,2,3};
//    cout << best_path(N,K,H,L);
//}

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57