add sol

leetcode/leetcode75/Backtracking/216.CombinationSumIII/combinationSumIII.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"fmt"
+)
+
+func combinationSum3(k int, n int) [][]int {
+	result := [][]int{}
+	t := []int{}
+	var dfs func(i, s int)
+	dfs = func(i, s int) {
+		if s == 0 {
+			if len(t) == k {
+				cp := make([]int, len(t))
+				copy(cp, t)
+				result = append(result, cp)
+			}
+			return
+		}
+		if i > 9 || i > s || len(t) >= k {
+			return
+		}
+		t = append(t, i)
+		dfs(i+1, s-i)
+		t = t[:len(t)-1]
+		dfs(i+1, s)
+	}
+	dfs(1, n)
+	return result
+}
+
+func main() {
+	k := 3
+	n := 7
+	fmt.Println(combinationSum3(k, n))
+}