<reponame>ZR-Huang/AlgorithmPractices
'''
Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.

Note:

The number of elements initialized in nums1 and nums2 are m and n respectively.

You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2.

Example:
Input:
nums1 = [1,2,3,0,0,0], m = 3
nums2 = [2,5,6],       n = 3

Output: [1,2,2,3,5,6]
'''

class Solution:
    def merge(self, nums1, m: int, nums2, n: int) -> None:
        """
        Do not return anything, modify nums1 in-place instead.
        """
        i = m + n - 1 # pointer for the ans
        m -= 1
        n -= 1
        while m >= 0 and n >= 0:
            if nums1[m] <= nums2[n]:
                nums1[i] = nums2[n]
                n -= 1
            else:
                nums1[i] = nums1[m]
                m -= 1
            i -= 1
        
        
        if m < 0: # if there are numbers left in nums2
            while n >= 0:
                nums1[i] = nums2[n]
                n -= 1
                i -= 1

        # there is no need to move the numbers left in nums1
'''
Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.

Note:

The number of elements initialized in nums1 and nums2 are m and n respectively.

You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2.

Example:
Input:
nums1 = [1,2,3,0,0,0], m = 3
nums2 = [2,5,6],       n = 3

Output: [1,2,2,3,5,6]
'''

class Solution:
    def merge(self, nums1, m: int, nums2, n: int) -> None:
        """
        Do not return anything, modify nums1 in-place instead.
        """
        i = m + n - 1 # pointer for the ans
        m -= 1
        n -= 1
        while m >= 0 and n >= 0:
            if nums1[m] <= nums2[n]:
                nums1[i] = nums2[n]
                n -= 1
            else:
                nums1[i] = nums1[m]
                m -= 1
            i -= 1
        
        
        if m < 0: # if there are numbers left in nums2
            while n >= 0:
                nums1[i] = nums2[n]
                n -= 1
                i -= 1

        # there is no need to move the numbers left in nums1
Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.  Note:  The number of elements initialized in nums1 and nums2 are m and n respectively.  You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2.  Example: Input: nums1 = [1,2,3,0,0,0], m = 3 nums2 = [2,5,6],       n = 3  Output: [1,2,2,3,5,6] Do not return anything, modify nums1 in-place instead. # pointer for the ans # if there are numbers left in nums2 # there is no need to move the numbers left in nums1