#include "race.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 200001;
const int K = 101;
vector<array<int, 2>> adj[N];
int dp[N][K];
int anc[N][30];
ll danc[N][30];
int h[N];
//int par[N];
int n, k;
array<ll, 2> lca(int a, int b)
{
if (h[a] < h[b]) swap(a, b);
ll dist = 0;
int edge = 0;
for (int i = 29; i >= 0; i--)
{
if (h[a] - (1 << i) >= h[b])
{
edge += 1 << i;
dist += danc[a][i];
a = anc[a][i];
}
}
if (a == b) return {edge, dist};
for (int i = 29; i >= 0; i--)
{
if (anc[a][i] != anc[b][i])
{
edge += 2 * (1 << i);
dist += danc[a][i];
dist += danc[b][i];
a = anc[a][i];
b = anc[b][i];
}
}
edge += 2;
dist += danc[a][0];
dist += danc[b][0];
return {edge, dist};
}
void dfs2(int node, int parent, int pdist)
{
if (parent == -1)
{
h[node] = 0;
for (int i = 0; i < 30; i++) anc[node][i] = -1;
for (int i = 0; i < 30; i++) danc[node][i] = -1;
} else
{
h[node] = h[parent] + 1;
anc[node][0] = parent;
danc[node][0] = pdist;
for (int i = 1; i < 30; i++)
{
if (anc[node][i - 1] == -1) anc[node][i] = -1;
else
{
anc[node][i] = anc[anc[node][i - 1]][i - 1];
}
}
for (int i = 1; i < 30; i++)
{
if (anc[node][i] == -1) danc[node][i] = -1;
else
{
danc[node][i] = danc[node][i - 1] + danc[anc[node][i - 1]][i - 1];
}
}
}
for (auto next : adj[node])
{
if (next[0] == parent) continue;
dfs2(next[0], node, next[1]);
}
}
int dfs1(int node, int parent)
{
dp[node][0] = 0;
//par[node] = parent;
int res = N;
vector<int> bestAt(k + 1, N);
bestAt[0] = 0;
for (auto next : adj[node])
{
if (next[0] == parent) continue;
res = min(res, dfs1(next[0], node));
for (int i = 0; i + next[1] <= k; i++)
{
//cout << node << " " << next[0] << " " << i << " " << dp[next[0]][i] << endl;
dp[node][i + next[1]] = min(dp[node][i + next[1]], dp[next[0]][i] + 1);
res = min(res, dp[next[0]][i] + 1 + bestAt[k - i - next[1]]);
}
for (int i = 0; i + next[1] <= k; i++)
{
bestAt[i + next[1]] = min(bestAt[i + next[1]], dp[next[0]][i] + 1);
}
}
return res;
}
int best_path(int n1, int k1, int H[][2], int L[])
{
n = n1;
k = k1;
for (int i = 0; i < n; i++) for (int j = 0; j <= k; j++) dp[i][j] = N;
for (int i = 0; i < n - 1; i++)
{
adj[H[i][0]].push_back({H[i][1], L[i]});
adj[H[i][1]].push_back({H[i][0], L[i]});
}
int res = N;
if (n > 1000)
{
res = dfs1(0, -1);
} else
{
dfs2(0, -1, -1);
for (int i = 0; i < n; i++)
{
for (int j = i + 1; j < n; j++)
{
auto curr = lca(i, j);
if (curr[1] == k) res = min<int>(curr[0], res);
}
}
}
if (res == N) return -1;
return res;
}
