[0496 the next bigger element] add C version

add C version for 0496: the next bigger element

Signed-off-by: liao junwu <andyliaowu5@163.com>

problems/0496.下一个更大元素I.md

@@ -195,6 +195,62 @@ public:
 建议大家把情况一二三想清楚了，先写出版本一的代码，然后在其基础上在做精简！
 
 ## 其他语言版本
+
+### C
+
+``` C
+/* 先用单调栈的方法计算出结果，再根据nums1中的元素去查找对应的结果 */
+/**
+ * Note: The returned array must be malloced, assume caller calls free().
+ */
+int* nextGreaterElement(int* nums1, int nums1Size, int* nums2, int nums2Size, int* returnSize) {
+
+    /* stcak */
+    int top = -1;
+    int stack_len = nums2Size;
+    int stack[stack_len];
+    //memset(stack, 0x00, sizeof(stack));
+
+    /* nums2 result */
+    int* result_nums2 = (int *)malloc(sizeof(int) * nums2Size);
+    //memset(result_nums2, 0x00, sizeof(int) * nums2Size);
+
+    /* result */
+    int* result = (int *)malloc(sizeof(int) * nums1Size);
+    //memset(result, 0x00, sizeof(int) * nums1Size);
+    *returnSize = nums1Size;
+
+    /* init */
+    stack[++top] = 0; /* stack loaded with array subscripts */
+
+    for (int i = 0; i < nums2Size; i++) {
+        result_nums2[i] = -1;
+    }
+
+    /* get the result_nums2 */
+    for (int i = 1; i < nums2Size; i++) {
+        if (nums2[i] <= nums2[stack[top]]) {
+            stack[++top] = i; /* push */
+        } else {
+            while ((top >= 0) && (nums2[i] > nums2[stack[top]])) {
+                result_nums2[stack[top]] = nums2[i];
+                top--; /* pop */
+            }
+            stack[++top] = i;
+        }
+    }
+
+    /* get the result */
+    for (int i = 0; i < nums1Size; i++) {
+        for (int j = 0; j < nums2Size; j++) {
+            if (nums1[i] == nums2[j]) {
+                result[i] = result_nums2[j];
+            }
+        }
+    }
+    return result;
+}
+```
 ### Java
 
 ```java