Merge pull request #135 from QuinnDK/添加0077组合Go版本

添加0077组合Go版本

problems/0077.组合.md

@@ -373,6 +373,32 @@ Python：
 
 
 Go：
+```Go
+var res [][]int 
+func combine(n int, k int) [][]int {
+   res=[][]int{}
+   if n <= 0 || k <= 0 || k > n {
+		return res
+	}
+    backtrack(n, k, 1, []int{})
+	return res
+}
+func backtrack(n,k,start int,track []int){
+    if len(track)==k{
+        temp:=make([]int,k)
+        copy(temp,track)
+        res=append(res,temp)
+    }
+    if len(track)+n-start+1 < k {
+			return
+		}
+    for i:=start;i<=n;i++{
+        track=append(track,i)
+        backtrack(n,k,i+1,track)
+        track=track[:len(track)-1]
+    }
+}
+```