4. Median of Two Sorted Arrays

문제

• Given two sorted arrays nums1 and nums2 of size m and n respectively, return the median of the two sorted arrays.
  

  Input: nums1 = [1,3], nums2 = [2]
  Output: 2.00000
  Explanation: merged array = [1,2,3] and median is 2.
  

  Example 2:
  
  • nums1.length == m
  • nums2.length == n
  • 0 <= m <= 1000
  • 0 <= n <= 1000
  • 1 <= m + n <= 2000
  • -106 <= nums1[i], nums2[i] <= 106
• Constraints:
• Input: nums1 = [1,2], nums2 = [3,4] Output: 2.50000 Explanation: merged array = [1,2,3,4] and median is (2 + 3) / 2 = 2.5.
• Example 1:
• The overall run time complexity should be O(log (m+n)).

 

https://leetcode.com/problems/median-of-two-sorted-arrays/

 

 

풀이

이미 정렬된 두개의 배열을 준다고 하여, 그냥 하나로 합쳐서 풀었다.

 

 

 

코드

class Solution {
    public double findMedianSortedArrays(int[] nums1, int[] nums2) {
        int i = 0, j = 0, z = 0;
        
        int[] nums = new int[nums1.length + nums2.length];
        while (i < nums1.length && j < nums2.length) {
            nums[z++] = nums1[i] < nums2[j] ? nums1[i++] : nums2[j++];
        }
         
        if (i == nums1.length) {
            for (; z < nums.length; z++) {
                nums[z] = nums2[j++];
            }
        }
        else {
            for (; z < nums.length; z++) {
                nums[z] = nums1[i++];
            }
        }
        
         
        if (nums.length % 2 == 0) {
        	return (double)(nums[nums.length / 2 - 1] + nums[nums.length / 2]) / 2;
        }
        else {
        	return nums[nums.length / 2]; 
        }
    }
}

 

 

결과

Runtime: 4 ms, faster than 60.76% of Java online submissions for Median of Two Sorted Arrays.

Memory Usage: 49.5 MB, less than 13.27% of Java online submissions for Median of Two Sorted Arrays.