fix(go): fix go code , refer to @joengtou @wcig @shenjq (#992)

codes/go/chapter_backtracking/preorder_traversal_ii_compact.go

@@ -17,7 +17,7 @@ func preOrderII(root *TreeNode, res *[][]*TreeNode, path *[]*TreeNode) {
 	*path = append(*path, root)
 	if root.Val.(int) == 7 {
 		// 记录解
-		*res = append(*res, *path)
+		*res = append(*res, append([]*TreeNode{}, *path...))
 	}
 	preOrderII(root.Left, res, path)
 	preOrderII(root.Right, res, path)

codes/go/chapter_hashing/hash_map_chaining.go

@@ -41,7 +41,7 @@ func (m *hashMapChaining) hashFunc(key int) int {
 
 /* 负载因子 */
 func (m *hashMapChaining) loadFactor() float64 {
-	return float64(m.size / m.capacity)
+	return float64(m.size) / float64(m.capacity)
 }
 
 /* 查询操作 */
@@ -66,9 +66,9 @@ func (m *hashMapChaining) put(key int, val string) {
 	}
 	idx := m.hashFunc(key)
 	// 遍历桶，若遇到指定 key ，则更新对应 val 并返回
-	for _, p := range m.buckets[idx] {
+	for i := range m.buckets[idx] {
-		if p.key == key {
+		if m.buckets[idx][i].key == key {
-			p.val = val
+			m.buckets[idx][i].val = val
 			return
 		}
 	}

codes/go/chapter_hashing/hash_map_open_addressing.go

@@ -88,6 +88,7 @@ func (m *hashMapOpenAddressing) put(key int, val string) {
 		// 若遇到指定 key ，则更新对应 val
 		if m.buckets[j].key == key {
 			m.buckets[j].val = val
+			return
 		}
 	}
 }