"""
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.


Note:

0 <= A.length < 1000
0 <= B.length < 1000
0 <= A[i].start, A[i].end, B[i].start, B[i].end < 10^9
NOTE: input types have been changed on April 15, 2019. Please reset to default code definition to get
new method signature.
"""


class Solution(object):
    def intervalIntersection(self, A, B):
        """
        :type A: List[List[int]]
        :type B: List[List[int]]
        :rtype: List[List[int]]
        """
        if len(A) == 0 or len(B) == 0:
            return [[]]
        result = []
        i, j = 0, 0
        while i < len(A) and j < len(B):
            a_point = A[i]
            b_point = B[j]

            intersection_point = []

            intersection_point[0] = max(a_point[0], b_point[0])
            intersection_point[1] = min(a_point[1], b_point[1])

            if intersection_point[0] <= intersection_point[1]:
                result.append(intersection_point)

            if a_point[1] < b_point[1]:
                i += 1
            elif a_point[1] == b_point[1]:
                i += 1
                j += 1
            else:
                j += 1

        return result
