結果

問題 No.1094 木登り / Climbing tree
ユーザー ccppjsrb
提出日時 2020-09-16 11:44:39
言語 Go
(1.23.4)
結果
AC  
実行時間 726 ms / 2,000 ms
コード長 3,573 bytes
コンパイル時間 15,145 ms
コンパイル使用メモリ 231,636 KB
実行使用メモリ 110,336 KB
最終ジャッジ日時 2024-11-08 07:08:02
合計ジャッジ時間 32,577 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge1
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 1
other AC * 26
権限があれば一括ダウンロードができます

ソースコード

diff # 

package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"math"
	"os"
	"strconv"
)

func configure(scanner *bufio.Scanner) {
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1000005), 1000005)
}
func getNextString(scanner *bufio.Scanner) string {
	scanned := scanner.Scan()
	if !scanned {
		panic("scan failed")
	}
	return scanner.Text()
}
func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}
func getNextInt64(scanner *bufio.Scanner) int64 {
	i, _ := strconv.ParseInt(getNextString(scanner), 10, 64)
	return i
}
func getNextFloat64(scanner *bufio.Scanner) float64 {
	i, _ := strconv.ParseFloat(getNextString(scanner), 64)
	return i
}
func main() {
	fp := os.Stdin
	wfp := os.Stdout
	extra := 0
	if os.Getenv("I") == "IronMan" {
		fp, _ = os.Open(os.Getenv("END_GAME"))
		extra = 100
	}
	scanner := bufio.NewScanner(fp)
	configure(scanner)
	writer := bufio.NewWriter(wfp)
	defer func() {
		r := recover()
		if r != nil {
			fmt.Fprintln(writer, r)
		}
		writer.Flush()
	}()
	solve(scanner, writer)
	for i := 0; i < extra; i++ {
		fmt.Fprintln(writer, "-----------------------------------")
		solve(scanner, writer)
	}
}
func solve(scanner *bufio.Scanner, writer *bufio.Writer) {
	n := getNextInt(scanner)
	g := newGraph(n)
	for i := 0; i < n-1; i++ {
		a := getNextInt(scanner) - 1
		b := getNextInt(scanner) - 1
		c := getNextInt(scanner)
		g.AppendEdge(a, b, i, c)
		g.AppendEdge(b, a, i, c)
	}
	for i := 0; i < n; i++ {
		g.v[i].c = math.MaxInt32
	}
	dd := &daikes{}
	heap.Push(dd, &daike{i: 0, c: 0})
	for dd.Len() > 0 {
		p := heap.Pop(dd).(*daike)
		if g.v[p.i].c <= p.c {
			continue
		}
		g.v[p.i].c = p.c
		for _, e := range g.e[p.i] {
			heap.Push(dd, &daike{i: e.to, c: p.c + e.c})
		}
	}
	g.Dfs(0, -1, 0)
	g.Doubling()
	q := getNextInt(scanner)
	for q > 0 {
		q--
		s := getNextInt(scanner) - 1
		t := getNextInt(scanner) - 1
		lca := g.Lca(s, t)
		fmt.Fprintln(writer, g.v[s].c+g.v[t].c-g.v[lca].c<<1)
	}
}

type daike struct {
	i int
	c int
}

type daikes []*daike

func (h daikes) Len() int { return len(h) }
func (h daikes) Less(i, j int) bool {
	return h[i].c < h[j].c
}
func (h daikes) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
func (h *daikes) Push(x interface{}) {
	*h = append(*h, x.(*daike))
}
func (h *daikes) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[0 : n-1]
	return x
}

type vertex struct {
	depth  int
	parent [32]int
	c      int
}
type edge struct {
	to, id int
	c      int
}
type graph struct {
	v []vertex
	e [][]edge
}

func newGraph(n int) graph {
	return graph{
		v: make([]vertex, n),
		e: make([][]edge, n),
	}
}
func (g *graph) AppendEdge(from, to, id int, c int) {
	g.e[from] = append(g.e[from], edge{
		to: to,
		id: id,
		c:  c,
	})
}
func (g *graph) Dfs(i, p, depth int) {
	g.v[i].parent[0] = p
	g.v[i].depth = depth
	for _, e := range g.e[i] {
		if e.to == p {
			continue
		}
		g.Dfs(e.to, i, depth+1)
	}
}
func (g *graph) Doubling() {
	for d := 1; d < 32; d++ {
		for i := 0; i < len(g.v); i++ {
			if g.v[i].parent[d-1] == -1 {
				g.v[i].parent[d] = -1
				continue
			}
			g.v[i].parent[d] = g.v[g.v[i].parent[d-1]].parent[d-1]
		}
	}
}
func (g *graph) Lca(u, v int) int {
	if g.v[u].depth > g.v[v].depth {
		u, v = v, u
	}
	d := g.v[v].depth - g.v[u].depth
	for i := 0; i < 32; i++ {
		if d>>uint(i)&1 == 1 {
			v = g.v[v].parent[i]
		}
	}
	if v == u {
		return v
	}
	for i := 31; i >= 0; i-- {
		if g.v[v].parent[i] == g.v[u].parent[i] {
			continue
		}
		v = g.v[v].parent[i]
		u = g.v[u].parent[i]
	}
	return g.v[v].parent[0]
}
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