88. Merge Sorted Array
Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.
Note:
You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2. The number of elements initialized in nums1 and nums2 are m and n respectively.
解法
归并排序。从后往前排。
public class Solution {
public void merge(int[] nums1, int m, int[] nums2, int n) {
if (nums1 == null || nums1.length == 0) {
return;
}
if (nums2 == null || nums2.length == 0) {
return;
}
int i = m - 1, j = n - 1, k = n + m - 1;
while (i >= 0 && j >= 0) {
if (nums1[i] >= nums2[j]) {
nums1[k--] = nums1[i--];
} else {
nums1[k--] = nums2[j--];
}
}
// 其实本步不太需要,因为剩下的元素都存在nums1中
while (k >= 0 && i >= 0) {
nums1[k--] = nums1[i--];
}
while (k >= 0 && j >= 0) {
nums1[k--] = nums2[j--];
}
}
}