350. Intersection of Two Arrays II
Easy
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.
Follow up:
- 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?
package leetcode.easy;
public class IntersectionOfTwoArraysII {
private static void print_arr(int[] nums) {
for (int num : nums) {
System.out.print(num + " ");
}
System.out.println();
}
public int[] intersect(int[] nums1, int[] nums2) {
int i = 0, j = 0, k = 0;
int len = nums1.length < nums2.length ? nums1.length : nums2.length;
int[] nums = new int[len];
java.util.Arrays.sort(nums1);
java.util.Arrays.sort(nums2);
while (i < nums1.length && j < nums2.length) {
if (nums1[i] < nums2[j]) {
i++;
} else if (nums1[i] > nums2[j]) {
j++;
} else {
nums[k++] = nums1[i];
i++;
j++;
}
}
return java.util.Arrays.copyOf(nums, k);
}
@org.junit.Test
public void test1() {
int[] nums1 = { 1, 2, 2, 1 };
int[] nums2 = { 2, 2 };
print_arr(intersect(nums1, nums2));
}
@org.junit.Test
public void test2() {
int[] nums1 = { 4, 9, 5 };
int[] nums2 = { 9, 4, 9, 8, 4 };
print_arr(intersect(nums1, nums2));
}
}