添加 0454.四数相加II go版本

problems/0454.四数相加II.md

@@ -154,6 +154,23 @@ class Solution(object):
 
 
 Go：
+```go
+func fourSumCount(nums1 []int, nums2 []int, nums3 []int, nums4 []int) int {
+    m := make(map[int]int)
+    count := 0
+    for _, v1 := range nums1 {
+        for _, v2 := range nums2 {
+            m[v1+v2]++
+        }
+    }
+    for _, v3 := range nums3 {
+        for _, v4 := range nums4 {
+            count += m[-v3-v4]
+        }
+    }
+    return count
+}
+```
 
 javaScript: