feat: add Determine if Two Strings Are Close (#1192)

* add leetcode Determine if Two Strings Are Close

* Update 1657.c

add comments

* Update leetcode/src/1657.c

Co-authored-by: David Leal <halfpacho@gmail.com>

leetcode/DIRECTORY.md

@@ -114,6 +114,7 @@
 | 1189 | [Maximum Number of Balloons](https://leetcode.com/problems/maximum-number-of-balloons/)                                         | [C](./src/1189.c) | Easy       |
 | 1207 | [Unique Number of Occurrences](https://leetcode.com/problems/unique-number-of-occurrences/)                                     | [C](./src/1207.c) | Easy       |
 | 1283 | [Find the Smallest Divisor Given a Threshold]https://leetcode.com/problems/find-the-smallest-divisor-given-a-threshold/description/)  | [C](./src/1283.c) | Medium       |
+| 1657 | [Determine if Two Strings Are Close](https://leetcode.com/problems/determine-if-two-strings-are-close/description/)             | [C](./src/1657.c) | Medium     |
 | 1695 | [Maximum Erasure Value](https://leetcode.com/problems/maximum-erasure-value/)                                                   | [C](./src/1695.c) | Medium     |
 | 1769 | [Minimum Number of Operations to Move All Balls to Each Box](https://leetcode.com/problems/minimum-number-of-operations-to-move-all-balls-to-each-box/)          | [C](./src/1769.c) | Medium     |
 | 1524 | [Number of Sub-arrays With Odd Sum](https://leetcode.com/problems/number-of-sub-arrays-with-odd-sum/)                           | [C](./src/1524.c) | Medium     |

leetcode/src/1657.c

@@ -0,0 +1,51 @@
+const charLength = 26;
+
+int* charsCount(char* word){
+    int* result = calloc(charLength, sizeof(int));
+    int wordLen = strlen(word);
+    for (int i = 0; i < wordLen; i++){
+        result[word[i] - 'a']++;
+    }
+
+    return result;
+}
+
+int diff(const int *i, const int *j)
+{
+    return *i - *j;
+}
+
+// Counting
+// Runtime: O(n)
+// Space: O(1)
+bool closeStrings(char * word1, char * word2){
+    int* word1CharsCounter = charsCount(word1);
+    int* word2CharsCounter = charsCount(word2);
+
+    // The lengths of both string should be equal
+    if (strlen(word1) != strlen(word2)){
+        return false;
+    }
+
+    // The char should appear in both strings
+    for (int i = 0; i < charLength; i++){
+        if ((word1CharsCounter[i] != 0 && word2CharsCounter[i] == 0) ||
+           (word1CharsCounter[i] == 0 && word2CharsCounter[i] != 0)){
+               return false;
+           }
+    }
+
+    qsort(word1CharsCounter, charLength, sizeof (int), (int(*) (const void *, const void *)) diff);
+    qsort(word2CharsCounter, charLength, sizeof (int), (int(*) (const void *, const void *)) diff);
+
+    // appearing of chars should be the same in both strings.
+    for (int i = 0; i < charLength; i++){
+        if (word1CharsCounter[i] != word2CharsCounter[i]){
+               return false;
+        }
+    }
+
+    free(word1CharsCounter);
+    free(word2CharsCounter);
+    return true;
+}