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Author: marchanbbb

17.电话号码的字母组合.go

@@ -0,0 +1,31 @@
+/*
+ * @lc app=leetcode.cn id=17 lang=golang
+ *
+ * [17] 电话号码的字母组合
+ */
+
+// @lc code=start
+func letterCombinations(digits string) []string {
+	if len(digits) == 0 {
+		return nil
+	}
+	n2m := []string{"abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"}
+	result := []string{""}
+	for i:=0; i<len(digits); i++ {
+		resultL := len(result)
+		for j := 0; j<resultL; j++ {
+			s := result[j]
+			for k, c := range n2m[digits[i]-'2'] {
+				v := s + string(c)
+				if k == 0 {
+					result[j] = v
+				} else {
+					result = append(result, v)
+				}
+			}
+		}
+	}
+	return result
+}
+// @lc code=end
+

39.组合总和.go

@@ -0,0 +1,32 @@
+/*
+ * @lc app=leetcode.cn id=39 lang=golang
+ *
+ * [39] 组合总和
+ */
+
+// @lc code=start
+func combinationSum(candidates []int, target int) [][]int {
+	sort.Ints(candidates)
+	result := make([][]int, 0)
+	list := make([]int, 0)
+	backtrack(candidates, list, target, 0, &result)
+	return result
+}
+
+func backtrack(candidates, list []int, target, pos int,result *[][]int) {
+	if target == 0 {
+		tmp := make([]int, len(list))
+		copy(tmp, list)
+		*result = append(*result, tmp)
+	}
+	for i := pos; i < len(candidates); i++ {
+		v := candidates[i]
+		if target < v {
+			break
+		}
+		backtrack(candidates, append(list, v), target-v, i, result)
+	}
+}
+
+// @lc code=end
+