LeetCode – Intersection of Two Arrays (Java)
Given two arrays, write a function to compute their intersection.
Java Solution 1  HashSet
Time = O(n).
Space = O(n).
public int[] intersection(int[] nums1, int[] nums2) { HashSet<Integer> set1 = new HashSet<Integer>(); for(int i: nums1){ set1.add(i); } HashSet<Integer> set2 = new HashSet<Integer>(); for(int i: nums2){ if(set1.contains(i)){ set2.add(i); } } int[] result = new int[set2.size()]; int i=0; for(int n: set2){ result[i++] = n; } return result; } 
Java Solution 2  Binary Search
Time = O(nlog(n)).
Space = O(n).
public int[] intersection(int[] nums1, int[] nums2) { Arrays.sort(nums1); Arrays.sort(nums2); ArrayList<Integer> list = new ArrayList<Integer>(); for(int i=0; i<nums1.length; i++){ if(i==0  (i>0 && nums1[i]!=nums1[i1])){ if(Arrays.binarySearch(nums2, nums1[i])>1){ list.add(nums1[i]); } } } int[] result = new int[list.size()]; int k=0; for(int i: list){ result[k++] = i; } return result; } 
Any improvement?
<pre><code> String foo = "bar"; </code></pre>

strmrdr

Praveen Singh

ryanlr

Anusha