package challenges.leetcode

/**
You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively.
Merge nums1 and nums2 into a single array sorted in non-decreasing order.
The final sorted array should not be returned by the function, but instead be stored inside the array nums1. To accommodate this, nums1 has a length of m + n, where the first m elements denote the elements that should be merged, and the last n elements are set to 0 and should be ignored. nums2 has a length of n.

Example 1:

Input: nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3
Output: [1,2,2,3,5,6]
Explanation: The arrays we are merging are [1,2,3] and [2,5,6].
The result of the merge is [1,2,2,3,5,6] with the underlined elements coming from nums1.
Example 2:

Input: nums1 = [1], m = 1, nums2 = [], n = 0
Output: [1]
Explanation: The arrays we are merging are [1] and [].
The result of the merge is [1].
Example 3:

Input: nums1 = [0], m = 0, nums2 = [1], n = 1
Output: [1]
Explanation: The arrays we are merging are [] and [1].
The result of the merge is [1].
Note that because m = 0, there are no elements in nums1. The 0 is only there to ensure the merge result can fit in nums1.

Constraints:

nums1.length == m + n
nums2.length == n
0 <= m, n <= 200
1 <= m + n <= 200
-109 <= nums1[i], nums2[j] <= 109

Follow up: Can you come up with an algorithm that runs in O(m + n) time?
 */
object MergeSortedArray {

    private fun merge(a: IntArray, m: Int, b: IntArray, n: Int) {
        var insertIndex = m + n - 1
        var indexA = m - 1
        var indexB = n - 1
        while (indexB >= 0) {
            if (indexA < 0) {
                a[insertIndex--] = b[indexB--]
                continue
            }

            if (b[indexB] >= a[indexA]) {
                a[insertIndex--] = b[indexB--]
                continue
            }

            a[insertIndex--] = a[indexA--]
        }
    }

    @JvmStatic
    fun main(args: Array<String>) {
        val a = intArrayOf(1, 2, 3, 0, 0, 0)
        merge(a, 3, intArrayOf(2, 5, 6), 3)
        println(a.joinToString())
    }
}
package challenges.leetcode

/**
You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively.
Merge nums1 and nums2 into a single array sorted in non-decreasing order.
The final sorted array should not be returned by the function, but instead be stored inside the array nums1. To accommodate this, nums1 has a length of m + n, where the first m elements denote the elements that should be merged, and the last n elements are set to 0 and should be ignored. nums2 has a length of n.

Example 1:

Input: nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3
Output: [1,2,2,3,5,6]
Explanation: The arrays we are merging are [1,2,3] and [2,5,6].
The result of the merge is [1,2,2,3,5,6] with the underlined elements coming from nums1.
Example 2:

Input: nums1 = [1], m = 1, nums2 = [], n = 0
Output: [1]
Explanation: The arrays we are merging are [1] and [].
The result of the merge is [1].
Example 3:

Input: nums1 = [0], m = 0, nums2 = [1], n = 1
Output: [1]
Explanation: The arrays we are merging are [] and [1].
The result of the merge is [1].
Note that because m = 0, there are no elements in nums1. The 0 is only there to ensure the merge result can fit in nums1.

Constraints:

nums1.length == m + n
nums2.length == n
0 <= m, n <= 200
1 <= m + n <= 200
-109 <= nums1[i], nums2[j] <= 109

Follow up: Can you come up with an algorithm that runs in O(m + n) time?
 */
object MergeSortedArray {

    private fun merge(a: IntArray, m: Int, b: IntArray, n: Int) {
        var insertIndex = m + n - 1
        var indexA = m - 1
        var indexB = n - 1
        while (indexB >= 0) {
            if (indexA < 0) {
                a[insertIndex--] = b[indexB--]
                continue
            }

            if (b[indexB] >= a[indexA]) {
                a[insertIndex--] = b[indexB--]
                continue
            }

            a[insertIndex--] = a[indexA--]
        }
    }

    @JvmStatic
    fun main(args: Array<String>) {
        val a = intArrayOf(1, 2, 3, 0, 0, 0)
        merge(a, 3, intArrayOf(2, 5, 6), 3)
        println(a.joinToString())
    }
}