update

LC1/4.go

@@ -0,0 +1,34 @@
+//go:build ignore
+
+// 组合的输出 从 n 个元素(1-n)中选取 r 个数
+package main
+
+import "fmt"
+
+var (
+	n    int
+	r    int
+	path []int
+)
+
+func dfs(x int) {
+	// Return
+	if len(path) >= r {
+		for _, v := range path {
+			fmt.Printf("%d ", v)
+		}
+		fmt.Printf("\n")
+		return
+	}
+	// Traverse
+	for i := x; i <= n; i++ {
+		path = append(path, i)
+		dfs(i + 1)
+		path = path[:len(path)-1]
+	}
+}
+
+func main() {
+	fmt.Scan(&n, &r)
+	dfs(1)
+}