- LeetCode 88
Variant#2: 
nums1: 
1	3	5	0	0
		|
		nums1Ptr

nums2: 
2	4
		|
		nums2Ptr

sortedArray:
1	2	3	4	5
				sortedPtr

Variant#3: 
nums1: 
1	2	3	4	5
|		
nums1Ptr
	|
	sortedPtr

nums2: 
	2	4
|
nums2Ptr

- LeetCode 287:
	   Time	   Space
Variant#1: O(n^2), O(1)
Variant#2: O(n),   O(n)
Variant#3: O(n),   O(1)
Relax the assumption: "We cannot change the elements of the array"

3	1	2	-4	3

n + 1; n = 4; [1, 4]
2 main observations: 
1. All of the values are positive
2. All of the values can be used as indexes

Variant#4: O(n), O(1)

3	1	2	4	3

4	1	2	3	3

3	1	2	3	4

nums[0] = 3, nums[nums[0]] = nums[3] = 3

- Two Sum

{1, 2, 3} and target: 3
output: {1, 2}

{1, 2, 4, 5}
 |  |
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