Jan 11, 2023 · Jan 11, 2023
diff --git a/c/0347-top-k-frequent-elements.c b/c/0347-top-k-frequent-elements.c
 // A structure to represent an element of the heap.
 typedef struct {
    int num;
    int count;
 } Heap;

 static int compareHeap(const void* x, const void* y) {
  return ((Heap*)y)->count - ((Heap*)x)->count;
 }

 /**
 * Note: The returned array must be malloced, assume caller calls free().
 */
 int* topKFrequent(int* nums, int numsSize, int k, int* returnSize){
    int hash[20001] = {0};
    Heap* heap;
    int *res;
    int i, j;
    int c = 0;

    for (i = 0; i < numsSize; i++) {
        hash[nums[i]+10000]++;
        if (hash[nums[i]+10000]) {
            c++;
        }
    }

    heap = (Heap*)malloc(sizeof(Heap) * c);
    memset(heap, 0, sizeof(Heap) * c);

    c = 0;
    for (i = 0; i < 20001; i++) {
        if(hash[i] > 0) {
            heap[c].num = i - 10000;
            heap[c].count = hash[i];
            c++;
        }
    }
    qsort(heap, c, sizeof(Heap), compareHeap);

    c = 0;
    res = (int*)malloc(sizeof(int) * k);
    for (i = 0; i < k; i++) {
        res[c++] = heap[i].num;
    }

    *returnSize = c;
    return res;
 }
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,49 @@
		// A structure to represent an element of the heap.
		typedef struct {
		int num;
		int count;
		} Heap;

		static int compareHeap(const void* x, const void* y) {
		return ((Heap)y)->count - ((Heap)x)->count;
		}

		/**
		* Note: The returned array must be malloced, assume caller calls free().
		*/
		int* topKFrequent(int* nums, int numsSize, int k, int* returnSize){
		int hash[20001] = {0};
		Heap* heap;
		int *res;
		int i, j;
		int c = 0;

		for (i = 0; i < numsSize; i++) {
		hash[nums[i]+10000]++;
		if (hash[nums[i]+10000]) {
		c++;
		}
		}

		heap = (Heap)malloc(sizeof(Heap) c);
		memset(heap, 0, sizeof(Heap) * c);

		c = 0;
		for (i = 0; i < 20001; i++) {
		if(hash[i] > 0) {
		heap[c].num = i - 10000;
		heap[c].count = hash[i];
		c++;
		}
		}
		qsort(heap, c, sizeof(Heap), compareHeap);

		c = 0;
		res = (int)malloc(sizeof(int) k);
		for (i = 0; i < k; i++) {
		res[c++] = heap[i].num;
		}

		*returnSize = c;
		return res;
		}