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b.go
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b.go
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package main
import . "github.com/EndlessCheng/codeforces-go/leetcode/testutil"
// github.com/EndlessCheng/codeforces-go
func solve(n int, edges []*Point, _ int, queries []*Point) []int64 {
g := make([][]int, n+1)
for _, e := range edges {
v, w := e.X, e.Y
g[v] = append(g[v], w)
g[w] = append(g[w], v)
}
// 另一种写法是直接在节点上打 lazy tag
type node struct{ dfn, size int }
nodes := make([]node, n+1)
dfn := 0
ids := make([]int, n+1)
var build func(v, fa int) int
build = func(v, fa int) int {
dfn++
nodes[v].dfn = dfn
ids[dfn] = v
sz := 1
for _, w := range g[v] {
if w != fa {
sz += build(w, v)
}
}
nodes[v].size = sz
return sz
}
build(1, 0)
diff := make([]int, n+2)
for _, q := range queries {
o := nodes[q.X]
diff[o.dfn] += q.Y
diff[o.dfn+o.size] -= q.Y
}
ans := make([]int64, n)
s := 0
for i := 1; i <= n; i++ {
s += diff[i]
ans[ids[i]-1] = int64(s)
}
return ans
}