- 167. Two Sum II - Input Array Is Sorted
- 26. Remove Duplicates from Sorted Array
- 83. Remove Duplicates from Sorted List
- 977. Squares of a Sorted Array
- 15. 3Sum
- 16. 3Sum Closest
- 3Sum Smaller (lc premium)
- 75. Sort Colors (also Dutch National Flag?)
- 18. 4Sum
- 844. Backspace String Compare This can be done with stacks (but that means extra memory) or with two pointers for no extra space
- 581. Shortest Unsorted Continuous Subarray
- From both ends, find where order is “broken”, then find the min and max values between those stops. Then, if there is a bigger than min element to the left, add the element to the left; and if there is a smaller element than max to the right, add it.