LC986.java

/*
986. Interval List Intersections

Given two lists of closed intervals, each list of intervals is pairwise disjoint and in sorted order.

Return the intersection of these two interval lists.

(Formally, a closed interval [a, b] (with a <= b) denotes the set of real numbers x with a <= x <= b.  The intersection of two closed intervals is a set of real numbers that is either empty, or can be represented as a closed interval.  For example, the intersection of [1, 3] and [2, 4] is [2, 3].)

 

Example 1:

Input: A = [[0,2],[5,10],[13,23],[24,25]], B = [[1,5],[8,12],[15,24],[25,26]]
Output: [[1,2],[5,5],[8,10],[15,23],[24,24],[25,25]]
Reminder: The inputs and the desired output are lists of Interval objects, and not arrays or lists.
*/

class Solution {
    public int[][] intervalIntersection(int[][] A, int[][] B) 
    {
        List<int[]> ans = new ArrayList();
        int i = 0, j = 0;
        
        while (i < A.length && j < B.length)
        {
            int low = Math.max(A[i][0], B[j][0]);
            int high = Math.min(A[i][1], B[j][1]);
            
            if (low <= high)
            {
                ans.add(new int[]{low, high});
            }
            
            if (A[i][1] < B[j][1])
                i++;
            else
                j++;
        }
        
        return ans.toArray(new int[ans.size()][]);
    }
}