Create 2001-number-of-pairs-of-interchangeable-rectangles.c

Create the C solution as the same solution in the YouTube video "https://www.youtube.com/watch?v=lEQ8ZlLOuyQ"

c/2001-number-of-pairs-of-interchangeable-rectangles.c

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+typedef struct hash_entry {
+ double* ratio; /* we'll use this field as the key */
+ long long count;
+ UT_hash_handle hh; /* makes this structure hashable */
+} hash_entry;
+
+long long interchangeableRectangles(int** rectangles, int rectanglesSize, int* rectanglesColSize){
+ hash_entry* ratioCountMap = NULL;
+ long long res = 0;
+
+ for(size_t i = 0; i < rectanglesSize; i++)
+ {
+ // Calculate the ratio (W / H)
+ double* ratio = (double*)malloc(sizeof(double));
+ *ratio = (double)rectangles[i][0] / rectangles[i][1];
+
+ hash_entry* retrievedMapEntry;
+ HASH_FIND_PTR(ratioCountMap, ratio, retrievedMapEntry);
+
+ // If the ratio already exists in the map then increment its count
+ if(retrievedMapEntry)
+ {
+ // Free the allocated memory for the ratio
+ free(ratio);
+ retrievedMapEntry->count += 1;
+ }
+ else
+ {
+ // If the ratio doesn't exist in the map then create a new map entry for it and add it to the map
+ hash_entry* mapEntryToAdd = (hash_entry*)malloc(sizeof(hash_entry)); 
+ mapEntryToAdd->ratio = ratio;
+ mapEntryToAdd->count = 1; 
+ HASH_ADD_KEYPTR(hh, ratioCountMap, mapEntryToAdd->ratio, sizeof(double), mapEntryToAdd);
+ }
+ }
+
+ for (hash_entry* retrievedMapEntry = ratioCountMap; retrievedMapEntry != NULL; retrievedMapEntry = retrievedMapEntry->hh.next)
+ {
+ res += (retrievedMapEntry->count * (retrievedMapEntry->count - 1)) / 2;
+ }
+
+ return res;
+}