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| #define REP(i, s, e) for (int i = s; i <= e ; i++)
#define DEBUG fprintf(stderr, "Passing [%s] in Line %d\n", __FUNCTION__, __LINE__)
#include <iostream>
#include <cstdio>
#define int long long
using namespace std;
const int maxn = 300000 + 10, maxm = maxn, inf = 1ll << 40;
int bg[maxn], ne[maxm << 1], to[maxm << 1], e;
void add(int x, int y)
{
e++;
to[e] = y;
ne[e] = bg[x];
bg[x] = e;
}
int depth[maxn];
void dfs(int x, int fa = -1)
{
for (int i = bg[x]; i ; i = ne[i])
if (to[i] ^ fa)
{
depth[to[i]] = depth[x] + 1;
dfs(to[i], x);
}
}
struct worker
{
int up, w, ne;
}p[maxm << 1];
int cur = 300000;
void insert(int x, int up, int w)
{
p[++cur] = (worker){up, w, p[x].ne};
p[x].ne = cur;
}
struct heap *null;
heap* merge(heap *x, heap *y){};
struct heap
{
int up, f, Min, tag, dis;
heap *l, *r;
void pushdown()
{
if (tag)
{
f += tag;
Min += tag;
l -> tag += tag;
r -> tag += tag;
tag = 0;
}
}
void pushup()
{
Min = min(f, min(l -> Min + l -> tag, r -> Min + r -> tag));
if (l -> dis < r -> dis) swap(l, r);
dis = r -> dis + 1;
}
void pop() {*this = merge(l, r);}
}pool[maxn], *now = pool, *root[maxn];
heap* merge(heap *x, heap *y)
{
if (x == null) return y;
if (y == null) return x;
x -> pushdown();y -> pushdown();
if (x -> up <= y -> up) swap(x, y);
x -> r = merge(x -> r, y);
x -> pushup();
return x;
}
void solve(int x, int fa = -1)
{
int sum = 0;
for (int i = bg[x]; i ; i = ne[i])
if (to[i] ^ fa)
{
solve(to[i], x);
while (root[to[i]] -> up >= depth[to[i]])
root[to[i]].pop();
if (root[to[i]] == null)
{
cout << -1 << endl;
exit(0);
}
sum += root[to[i]] -> Min;
}
for (int i = p[x].ne; i ; i = p[i].ne)
{
*now = (heap) {p[i].up, sum + p[i].w, sum + p[i].w, 0, 1, null, null};
root[x] = merge(root[x], now++);
}
for (int i = bg[x]; i ; i = ne[i])
if (to[i] ^ fa)
{
int Min = root[to[i]] -> Min;
root[to[i]] -> tag += sum - Min;
root[x] = merge(root[x], root[to[i]]);
}
if (root[x] == null)
{
cout << -1 << endl;
exit(0);
}
}
int m, n, k;
signed main()
{
#ifndef ONLINE_JUDGE
freopen("A.in", "r", stdin);
freopen("A.out", "w", stdout);
#endif
cin >> n >> m;
REP(i, 2, n)
{
int x, y;
scanf("%lld%lld", &x, &y);
add(x, y);add(y, x);
}
depth[1] = 1;
dfs(1);
REP(i, 1, m)
{
int u, v, w;
scanf("%lld%lld%lld", &u, &v, &w);
insert(u, depth[v], w);
}
null = new heap;
null -> l = null -> r = null;
null -> Min = inf;
REP(i, 1, n) root[i] = null;
solve(1);
printf("%lld\n", root[1] -> Min + root[1] -> tag);
return 0;
}
|
