update

LC1/3.go

@@ -0,0 +1,39 @@
+//go:build ignore
+
+// 输出自然数 1-n 的全排列
+package main
+
+import "fmt"
+
+var (
+	n    int
+	path []int
+	used []bool
+)
+
+func dfs() {
+	if len(path) == n {
+		for _, v := range path {
+			fmt.Printf("%d ", v)
+		}
+		fmt.Printf("\n")
+		return
+	}
+
+	for i := 1; i <= n; i++ {
+		if used[i] {
+			continue
+		}
+		used[i] = true
+		path = append(path, i)
+		dfs()
+		path = path[:len(path)-1]
+		used[i] = false
+	}
+}
+
+func main() {
+	fmt.Scan(&n)
+	used = make([]bool, n+1)
+	dfs()
+}