From 26f3ee6c93c7ed53a3d98ba1f92fbc8d295dfcb8 Mon Sep 17 00:00:00 2001
From: X-shuffle <53906918+X-shuffle@users.noreply.github.com>
Date: Sat, 19 Jun 2021 23:23:34 +0800
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添加 0040.组合总和II go版本
---
 problems/0040.组合总和II.md | 42 +++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/problems/0040.组合总和II.md b/problems/0040.组合总和II.md
index a462b524..021bba94 100644
--- a/problems/0040.组合总和II.md
+++ b/problems/0040.组合总和II.md
@@ -314,6 +314,48 @@ class Solution:
 ```
 Go：
 
+
+> 主要在于如何在回溯中去重
+
+```go
+func combinationSum2(candidates []int, target int) [][]int {
+    var trcak []int
+    var res [][]int
+    var history map[int]bool
+    history=make(map[int]bool)
+    sort.Ints(candidates)
+    backtracking(0,0,target,candidates,trcak,&res,history)
+    return res
+}
+func backtracking(startIndex,sum,target int,candidates,trcak []int,res *[][]int,history map[int]bool){
+    //终止条件
+    if sum==target{
+        tmp:=make([]int,len(trcak))
+        copy(tmp,trcak)//拷贝
+        *res=append(*res,tmp)//放入结果集
+        return
+    }
+    if sum>target{return}
+    //回溯
+    // used[i - 1] == true，说明同一树支candidates[i - 1]使用过
+    // used[i - 1] == false，说明同一树层candidates[i - 1]使用过
+    for i:=startIndex;i<len(candidates);i++{
+        if i>0&&candidates[i]==candidates[i-1]&&history[i-1]==false{
+                continue
+        }
+        //更新路径集合和sum
+        trcak=append(trcak,candidates[i])
+        sum+=candidates[i]
+        history[i]=true
+        //递归
+        backtracking(i+1,sum,target,candidates,trcak,res,history)
+        //回溯
+        trcak=trcak[:len(trcak)-1]
+        sum-=candidates[i]
+        history[i]=false
+    }
+}
+```
 javaScript： 
 
 ```js