package two_pointer; import java.util.Arrays; class MergeSortedArray { public static void main(String[] args) { // int[] num1 = new int[]{1, 2, 3, 0, 0, 0}; int[] num1 = new int[]{4, 5, 6, 0, 0, 0}; // new Solution().merge(num1, 3, new int[]{2, 5, 6}, 3); new MergeSortedArray().merge1(num1, 3, new int[]{1, 2, 3}, 3); System.out.println(Arrays.toString(num1)); } public void merge1(int[] nums1, int m, int[] nums2, int n) { if (m + n != nums1.length || n < 1) { return; } int[] new_arr = Arrays.copyOf(nums1, m); int i = 0; int k = 0; int current = 0; while (i < m && k < n) { int num1 = new_arr[i]; int num2 = nums2[k]; if (num1 > num2) { nums1[current] = num2; k++; } else { nums1[current] = num1; i++; } current++; } while (i < m) { nums1[current] = new_arr[i]; current++; i++; } while (k < n) { nums1[current] = nums2[k]; current++; k++; } } // more efficient public void merge2(int[] nums1, int m, int[] nums2, int n) { if (m + n != nums1.length || n < 1) { return; } int p1 = m - 1; int p2 = n - 1; int p3 = nums1.length - 1; while (p1 >= 0 && p2 >= 0) { int num1 = nums1[p1]; int num2 = nums2[p2]; if (num1 > num2) { nums1[p3] = num1; p1--; } else { nums1[p3] = num2; p2--; } p3--; } while (p2 >= 0) { nums1[p3] = nums2[p2]; p2--; p3--; } } }