Merge Sorted Array
You are given two sorted integer arrays nums1 and nums2, and integers m and n representing the number of elements in each.
Merge nums2 into nums1 in-place so that nums1 is sorted. nums1 has length m + n with the last n elements set to 0 (placeholders).
Output the merged array as space-separated integers.
Example:
1,2,3,0,0,0 3 2,5,6 3
1 2 2 3 5 6
- The input array
nums1is[1, 2, 3, 0, 0, 0]withm = 3valid elements, andnums2is[2, 5, 6]withn = 3elements. - We merge
nums2intonums1in-place, starting from the end of both arrays, comparing elements and placing the larger one at the end ofnums1. - The merge process involves iterating through both arrays, resulting in the following steps:
- Comparing
3fromnums1and6fromnums2, placing6at the end ofnums1. - Comparing
2fromnums1and5fromnums2, placing5at the second last position ofnums1. - Comparing
2fromnums1and2fromnums2, placing2at the third last position ofnums1, and the remaining2fromnums1is placed before it.
- Comparing
- The final output is the merged and sorted array
[1, 2, 2, 3, 5, 6].
Constraints:
- 0 <= m, n <= 200
- 1 <= m + n <= 200
- -10^9 <= nums1[i], nums2[i] <= 10^9
Background Knowledge
The problem involves merging two sorted arrays into a single sorted array. To understand this, it's essential to have a grasp of arrays and their operations. In programming, an array is a collection of elements of the same data type stored in contiguous memory locations. Arrays are indexed, meaning each element is assigned a unique index that allows for efficient access and manipulation.
The concept of in-place modification is also crucial. In-place algorithms operate directly on the input data structure, modifying it without creating additional storage. This approach is often preferred for its efficiency, as it minimizes memory usage. In the context of this problem, merging nums2 into nums1 in-place means that we will modify nums1 directly, without creating a new array to store the merged result.
Understanding sorted arrays is also vital. A sorted array is one where the elements are arranged in a specific order, either ascending or descending. The problem states that both nums1 and nums2 are sorted, which provides a significant advantage in terms of the merging process. We can leverage the existing order to efficiently combine the two arrays into a single sorted array.
Algorithm/Approach
The general approach to solving this type of problem involves using a two-pointer technique. This technique is commonly used in array and string problems, where two pointers are used to traverse the input data structures. In this case, we can use two pointers to iterate through nums1 and nums2, comparing elements and placing them in the correct order in nums1.
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