leetcode(88) merge sorted array 解法

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:

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

Output: [1,2,2,3,5,6]

解法

这题就是Mergesort里的merge函数,用两个指针就好啦,注意为空的判断和数组完结的处理

具体代码如下:

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class  {
public void merge(int[] nums1, int m, int[] nums2, int n) {
if (n == 0) {
return;
}
int[] res = new int[m + n];
int i = 0;
int j = 0;
int k = 0;
for (; k < m + n; k++) {
if (i == m) {
break;
}
if (j == n) {
break;
}
if (nums1[i] < nums2[j]) {
res[k] = nums1[i++];
} else {
res[k] = nums2[j++];
}
}
if (i == m) {
while (j < n) {
res[k++] = nums2[j++];
}
}
if (j == n) {
while (i < m) {
res[k++] = nums1[i++];
}
}
for (k = 0; k < m + n; k++) {
nums1[k] = res[k];
}
}
}