[Leetcode] 986. Interval List Intersections

class Solution:
    def intervalIntersection(self, firstList: List[List[int]], secondList: List[List[int]]) -> List[List[int]]:
        
        answer = []
        i, j = 0, 0

        if len(firstList) == 0 or len(secondList) == 0:
            return []

        while i < len(firstList) and j < len(secondList):
            if firstList[i][1] < secondList[j][0]:
                i += 1
            elif secondList[j][1] < firstList[i][0]:
                j += 1
            else:
                intersection_start = max(firstList[i][0], secondList[j][0])
                intersection_end = min(firstList[i][1], secondList[j][1])
                answer.append([intersection_start, intersection_end])
                if firstList[i][1] < secondList[j][1]:
                    i += 1
                else:
                    j += 1

        return answer

 

더 간단한 접근

class Solution:
    def intervalIntersection(self, A, B):
        i, j, ans = 0, 0, []
        
        while i < len(A) and j < len(B):
            curr = [max(A[i][0], B[j][0]), min(A[i][1], B[j][1])]
            if curr[0] <= curr[1]:
                ans.append(curr)
            if A[i][1] <= B[j][1]:
                i += 1
            else:
                j += 1

        return ans