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Array Part2

Two pointers 977 Squares of a Sorted Array      We can use two pointers to read the positive and negative parts of the array - one pointer  j  in the positive direction, and another  i  in the negative direction. Now that we are reading two increasing arrays (the squares of the elements), we can merge these arrays together using a two-pointer technique. 11 Container With Most Water      O(N) time and O(1) space, since better candidadates must use the taller line of l and r therefore we can use two pointer keep moving towards each other until they meet. Always abandon the shorter line while moving. 80 Remove Duplicates from Sorted Array II      tail = 0; for (int i = 0;  i < nums.size(); i++)           if (i < 2 || nums[i] > nums[tail - 2]) // not included twice yet                 nums[tail++] = nums...