https://leetcode.com/problems/find-k-th-smallest-pair-distance/description/

`k`th smallest pairs diff in array #hard #binary_search #two_pointers

https://leetcode.com/problems/longest-subarray-with-maximum-bitwise-and/description/

Max bitwise AND subarray #medium #bit_manipulation #two_pointers

https://leetcode.com/problems/find-the-longest-substring-containing-vowels-in-even-counts/description/

Longest substring with even number of "aeiou" #medium #bit_manipulation #two_pointers

https://leetcode.com/problems/permutation-in-string/description/


Is s2 contains permutation of s1? #medium #two_pointers

https://leetcode.com/problems/minimum-number-of-swaps-to-make-the-string-balanced/description/


Min swaps to balance brackets #medium #two_pointers #stack