胡乱break确实容易遗漏

18.四数之和.go

@@ -0,0 +1,49 @@
+/*
+ * @lc app=leetcode.cn id=18 lang=golang
+ *
+ * [18] 四数之和
+ */
+
+// @lc code=start
+func fourSum(nums []int, target int) [][]int {
+	sort.Ints(nums)
+	var res [][]int
+	var m = make(map[string]bool)
+	l := len(nums)
+	if l < 4 {
+		return res
+	}
+	for i := 0; i < l-3; i++ {
+		if nums[i]+nums[i+1]+nums[i+2]+nums[i+3] > target {
+			break
+		}
+		for j := i + 1; j < l-2; j++ {
+			if nums[i]+nums[j]+nums[j+1]+nums[j+2] > target {
+				break
+			}
+			left, right := j+1, l-1
+			for left < right {
+				sum := nums[i] + nums[j] + nums[left] + nums[right]
+				if sum == target {
+					key := fmt.Sprintf("%d#%d#%d#%d", nums[i], nums[j], nums[left], nums[right])
+					if _, ok := m[key]; !ok {
+						m[key] = true
+						res = append(res, []int{nums[i], nums[j], nums[left], nums[right]})
+					}
+
+					left++
+				}
+				if sum > target {
+					right--
+				}
+				if sum < target {
+					left++
+				}
+			}
+		}
+	}
+	return res
+}
+
+// @lc code=end
+