Merge pull request neetcode-gh#902 from FahadulShadhin/c-solutions

Adding 217-Contains-Duplicate.c

Author: Ahmad-A0

c/217-Contains-Duplicate.c

@@ -0,0 +1,42 @@
+/*
+    Time: O(n)
+    Space: O(1)
+*/
+
+typedef struct {
+	int key;
+	UT_hash_handle hh; // Makes this structure hashable
+} hash_table;
+
+hash_table *hash = NULL, *elem, *tmp;
+
+bool containsDuplicate(int* nums, int numsSize){
+    if (numsSize == 1) {
+      return false;
+    }
+    
+    bool flag = false;
+    
+    for (int i=0; i<numsSize; i++) {
+        HASH_FIND_INT(hash, &nums[i], elem);
+        
+        if(!elem) {
+           elem = malloc(sizeof(hash_table));
+           elem->key = nums[i];
+           HASH_ADD_INT(hash, key, elem);
+            
+           flag = false;
+       }
+       else {
+           flag = true;
+           break;
+       }
+    }
+                          
+    // Free up the hash table 
+	HASH_ITER(hh, hash, elem, tmp) {
+		HASH_DEL(hash, elem); free(elem);
+	}
+    
+    return flag;
+}