Two pointers
Moving two indices toward or alongside each other to prune a quadratic search.
Solved
0/8
1Valid Palindromeopposite endsEasy2Remove Duplicates from Sorted Arrayslow and fast · in-placeEasy3Merge Sorted Arraymerge · backward fillEasy4Two Sum II - Input Array Is Sortedopposite ends · sorted inputMedium53Sumsort + two pointers · dedupMedium6Container With Most Wateropposite ends · greedy eliminationMedium74Sumsort + two pointers · dedupMedium8Trapping Rain Wateropposite ends · running maxHard