合并区间

def solve():
    def merge(____):
        if not intervals:
            return []
        intervals.sort(____)
        result = [intervals[____]]
        for interval in intervals[____:]:
            if interval[____] <= result[-____][____]:
                result[-____][____] = max(____)
            else:
                result.append(____)
        return result
    print(merge(____))