diff --git a/problems/0454.四数相加II.md b/problems/0454.四数相加II.md
index 3baeade5..a0bf84da 100644
--- a/problems/0454.四数相加II.md
+++ b/problems/0454.四数相加II.md
@@ -418,20 +418,19 @@ public int FourSumCount(int[] nums1, int[] nums2, int[] nums3, int[] nums4) {
 // 哈希表大小
 const int HASH_SIZE = 101;
 
-typedef struct node
-{
+typedef struct node {
     int val;
     int count;
     struct node *next;
-}node, *HashMap;
+} node, *HashMap;
 
 // 哈希表插入
-void hash_insert(HashMap hashmap[], int val){
+void hash_insert(HashMap hashmap[], int val) {
     int idx = val < 0 ? (-val) % HASH_SIZE : val % HASH_SIZE, count = 0;
     node *p = hashmap[idx];
     while (p->next != NULL) {
         p = p->next;
-        if (p->val == val){
+        if (p->val == val) {
             (p->count)++;
             return;
         }
@@ -445,10 +444,10 @@ void hash_insert(HashMap hashmap[], int val){
 }
 
 // 哈希表查找
-int hash_search(HashMap hashmap[], int val){
+int hash_search(HashMap hashmap[], int val) {
     int idx = val < 0 ? (-val) % HASH_SIZE : val % HASH_SIZE;
     node *p = hashmap[idx];
-    while (p->next != NULL){
+    while (p->next != NULL) {
         p = p->next;
         if (p->val == val) return p->count;
     }
@@ -458,23 +457,23 @@ int hash_search(HashMap hashmap[], int val){
 int fourSumCount(int* nums1, int nums1Size, int* nums2, int nums2Size, int* nums3, int nums3Size, int* nums4, int nums4Size){
     // 初始化哈希表
     HashMap hashmap[HASH_SIZE];
-    for (int i = 0; i < HASH_SIZE; i++){
+    for (int i = 0; i < HASH_SIZE; i++) {
         hashmap[i] = malloc(sizeof(node));
         hashmap[i]->next = NULL;
     }
     
     // 统计两个数组元素之和的负值和出现的次数，放到哈希表中
     int count = 0, num;
-    for (int i=0; i<nums1Size; i++){
-        for(int j=0; j<nums2Size; j++){
+    for (int i = 0; i < nums1Size; i++) {
+        for(int j = 0; j < nums2Size; j++) {
             num = - nums1[i] - nums2[j];
             hash_insert(hashmap, num);
         }
     }
     
     // 统计另外两个数组元素之和，查找哈希表中对应元素的出现次数，加入总次数
-    for (int i=0; i<nums3Size; i++){
-        for(int j=0; j<nums4Size; j++){
+    for (int i = 0; i < nums3Size; i++) {
+        for(int j = 0; j < nums4Size; j++) {
             num = nums3[i] + nums4[j];
             count += hash_search(hashmap, num);
         }