From cd03a5b79a5deb90e444d46ba4c22cffd9478440 Mon Sep 17 00:00:00 2001
From: markwang <www.wang61@qq.com>
Date: Tue, 7 May 2024 10:57:05 +0800
Subject: [PATCH] =?UTF-8?q?15.=E4=B8=89=E6=95=B0=E4=B9=8B=E5=92=8C?=
 =?UTF-8?q?=E5=A2=9E=E5=8A=A0Go=E5=93=88=E5=B8=8C=E8=A7=A3=E6=B3=95?=
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---
 problems/0015.三数之和.md | 37 +++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/problems/0015.三数之和.md b/problems/0015.三数之和.md
index ae218385..f7146907 100644
--- a/problems/0015.三数之和.md
+++ b/problems/0015.三数之和.md
@@ -403,6 +403,7 @@ class Solution:
 ```
 
 ### Go：
+（版本一） 双指针
 
 ```Go
 func threeSum(nums []int) [][]int {
@@ -442,6 +443,42 @@ func threeSum(nums []int) [][]int {
 	return res
 }
 ```
+（版本二） 哈希解法
+
+```Go
+func threeSum(nums []int) [][]int {
+    res := make([][]int, 0)
+    sort.Ints(nums)
+    // 找出a + b + c = 0
+    // a = nums[i], b = nums[j], c = -(a + b)
+    for i := 0; i < len(nums); i++ {
+        // 排序之后如果第一个元素已经大于零，那么不可能凑成三元组
+        if nums[i] > 0 {
+            break
+        }
+        // 三元组元素a去重
+        if i > 0 && nums[i] == nums[i-1] {
+            continue
+        }
+        set := make(map[int]struct{})
+        for j := i + 1; j < len(nums); j++ {
+            // 三元组元素b去重
+            if j > i + 2 && nums[j] == nums[j-1] && nums[j-1] == nums[j-2] {
+                continue
+            }
+            c := -nums[i] - nums[j]
+            if _, ok := set[c]; ok {
+                res = append(res, []int{nums[i], nums[j], c})
+                // 三元组元素c去重
+                delete(set, c)
+            } else {
+                set[nums[j]] = struct{}{}
+            }
+        }
+    }
+    return res
+}
+```
 
 ### JavaScript: