2021-06-05 boj 16947

baekjoon/16947.go

@@ -0,0 +1,98 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+)
+
+var (
+	w  = bufio.NewWriter(os.Stdout)
+	sc = bufio.NewScanner(os.Stdin)
+)
+
+var (
+	N      int
+	check  []int
+	check2 []bool
+	D      []int
+	G      [][]int
+)
+
+func init() {
+	sc.Split(bufio.ScanWords)
+}
+
+func main() {
+	defer w.Flush()
+	N = scanInt()
+	check = make([]int, N+1)
+	check2 = make([]bool, N+1)
+	D = make([]int, N+1)
+	G = make([][]int, N+1)
+	for i := 0; i < N; i++ {
+		u, v := scanInt(), scanInt()
+		G[u] = append(G[u], v)
+		G[v] = append(G[v], u)
+	}
+
+	// cycle부터 찾는다.
+	solve(1, -1)
+
+	// cycle에서 시작하여 연결된 노드를 찾는다.
+	for i := 1; i <= N; i++ {
+		if check[i] == 2 && !check2[i] {
+			q := make([]int, 0)
+			q = append(q, i)
+			check2[i] = true
+			for len(q) != 0 {
+				cur := q[0]
+				q = q[1:]
+				for j := range G[cur] {
+					next := G[cur][j]
+					if check[next] != 2 && !check2[next] {
+						check2[next] = true
+						D[next] = D[cur] + 1
+						q = append(q, next)
+					}
+				}
+			}
+		}
+	}
+
+	for i := 1; i <= N; i++ {
+		fmt.Fprintf(w, "%d ", D[i])
+	}
+}
+
+func solve(node, prev int) int {
+	if check[node] == 1 {
+		return node
+	}
+	check[node] = 1
+	for i := range G[node] {
+		next := G[node][i]
+		if next == prev {
+			continue
+		}
+		res := solve(next, node)
+		if res == -2 {
+			return -2
+		}
+		if res >= 0 {
+			check[node] = 2
+			if node == res {
+				return -2
+			}
+			return res
+		}
+	}
+	return -1
+}
+
+func scanInt() int {
+	sc.Scan()
+	n, _ := strconv.Atoi(sc.Text())
+	return n
+}