0350. Intersection of Two Arrays I I

350. Intersection of Two Arrays II#

题目 #

Given two arrays, write a function to compute their intersection.

Example 1:

``````
Input: nums1 = [1,2,2,1], nums2 = [2,2]
Output: [2,2]

``````

Example 2:

``````
Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4]
Output: [4,9]

``````

Note:

• Each element in the result should appear as many times as it shows in both arrays.
• The result can be in any order.

• What if the given array is already sorted? How would you optimize your algorithm?
• What if nums1’s size is small compared to nums2’s size? Which algorithm is better?
• What if elements of nums2 are stored on disk, and the memory is limited such that you cannot load all elements into the memory at once?

代码 #

``````
package leetcode

func intersect(nums1 []int, nums2 []int) []int {
m := map[int]int{}
var res []int
for _, n := range nums1 {
m[n]++
}
for _, n := range nums2 {
if m[n] > 0 {
res = append(res, n)
m[n]--
}
}
return res
}

``````

Sep 6, 2020