#777055 (Go) No.1639 最小通信路

• 問題: No.1639 最小通信路
• ユーザー: Hima
• 提出日時: 2022-07-09 17:37:07
• 言語: Go (1.23.4)
• 結果: AC
• 実行時間: 6 ms / 2,000 ms
• コード長: 2,272 bytes
• コンパイル時間: 11,922 ms
• コンパイル使用メモリ: 222,856 KB
• 実行使用メモリ: 6,824 KB
• 最終ジャッジ日時: 2024-12-31 06:01:36
• 合計ジャッジ時間: 14,183 ms
• ジャッジサーバーID （参考情報）: judge5 / judge4

ファイルパターン	結果
sample	AC * 2
other	AC * 43

ソースコード

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package main
import (
    "bufio"
    "fmt"
    "os"
    "strconv"
)
var sc = bufio.NewScanner(os.Stdin)
var out = bufio.NewWriter(os.Stdout)
func solve(n int, a, b []int, c []string) string {
    uf := NewUnionFind(n)
    m := n * (n - 1) / 2
    for i := 0; i < m; i++ {
        uf.Unite(a[i], b[i])
        if uf.Size(1) == n {
            return c[i]
        }
    }
    return c[m-1]
}
func main() {
    buf := make([]byte, 1024*1024)
    sc.Buffer(buf, bufio.MaxScanTokenSize)
    sc.Split(bufio.ScanWords)
    n := nextInt()
    var a, b []int
    var c []string
    for i := 0; i < n*(n-1)/2; i++ {
        a = append(a, nextInt())
        b = append(b, nextInt())
        c = append(c, nextString())
    }
    ans := solve(n, a, b, c)
    PrintString(ans)
}
func nextInt() int {
    sc.Scan()
    i, _ := strconv.Atoi(sc.Text())
    return i
}
func nextString() string {
    sc.Scan()
    return sc.Text()
}
func PrintString(x string) {
    defer out.Flush()
    fmt.Fprintln(out, x)
}
type UnionFind struct {
    par  []int // parent numbers
    rank []int // height of tree
    size []int
}
func NewUnionFind(n int) *UnionFind {
    if n <= 0 {
        return nil
    }
    u := new(UnionFind)
    // for accessing index without minus 1
    u.par = make([]int, n+1)
    u.rank = make([]int, n+1)
    u.size = make([]int, n+1)
    for i := 0; i <= n; i++ {
        u.par[i] = i
        u.rank[i] = 0
        u.size[i] = 1
    }
    return u
}
func (this *UnionFind) Find(x int) int {
    if this.par[x] == x {
        return x
    } else {
        // compress path
        // ex. Find(4)
        // 1 - 2 - 3 - 4
        // 1 - 2
        //  L-3
        //  L 4
        this.par[x] = this.Find(this.par[x])
        return this.par[x]
    }
}
func (this *UnionFind) Size(x int) int {
    return this.size[this.Find(x)]
}
func (this *UnionFind) ExistSameUnion(x, y int) bool {
    return this.Find(x) == this.Find(y)
}
func (this *UnionFind) Unite(x, y int) {
    x = this.Find(x)
    y = this.Find(y)
    if x == y {
        return
    }
    // rank
    if this.rank[x] < this.rank[y] {
        //yがrootの木にxがrootの木を結合する
        this.par[x] = y
        this.size[y] += this.size[x]
    } else {
        // this.rank[x] >= this.rank[y]
        //xがrootの木にyがrootの木を結合する
        this.par[y] = x
        this.size[x] += this.size[y]
        if this.rank[x] == this.rank[y] {
            this.rank[x]++
        }
    }
}
func PrintUnionFind(u *UnionFind) {
    // for debuging. not optimize.
    fmt.Println(u.par)
    fmt.Println(u.rank)
    fmt.Println(u.size)
}
 
 
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