# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
674198 | Megumin2006 | Race (IOI11_race) | 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 "race.h"
#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define ed '\n'
#define pb push_back
#define int long long
#define ii pair<int,int>
#define fi first
#define se second
using namespace std;
const int N = 2e5 + 10;
ii lazy[N];
vector<ii> g[N];
int n, k, ans = 1e18;
map<int, int> f[N];
void Merge(int u, int v) {
if (f[u].size() < f[v].size()) {
swap(lazy[u], lazy[v]);
f[u].swap(f[v]);
}
for(pair<int, int> tmp: f[v]) {
int num = tmp.fi + lazy[v].fi;
int Min = tmp.se + lazy[v].se;
auto t = f[u].find(k - num - lazy[u].fi);
if (t != f[u].end()) {
if (t->se + Min + lazy[u].se < ans) {
ans = t->se + Min + lazy[u].se;
}
}
if (f[u][num - lazy[u].fi] == 0) f[u][num - lazy[u].fi] = Min - lazy[u].se;
else {
if (Min - lazy[u].se < f[u][num - lazy[u].fi]) {
f[u][num - lazy[u].fi] = Min - lazy[u].se;
}
}
}
}
void dfs(int u, int p, int val) {
f[u][0] = 0;
for(ii &e: g[u]) if (e.fi != p) {
dfs(e.fi, u, e.se);
Merge(u, e.fi);
}
lazy[u].fi += val;
lazy[u].se ++;
}
int best_path(int N, int K, int H[][2], int L[]) {
n = N, k = K;
for(int i=0;i<n-1;i++)
{
g[H[i][0]+1].pb({H[i][1]+1,L[i]});
g[H[i][1]+1].pb({H[i][0]+1,L[i]});
}
dfs(0, -1, 0);
if (ans == 1e18) ans = -1;
return ans;
}