218. The Skyline Problem-Hard

一、题目描述

　　　　给定建筑的轮廓坐标，求叠加之后的轮廓结果

二、解法

　　这个题目最容易想到的思路是扫描法

　　　　https://briangordon.github.io/2014/08/the-skyline-problem.html

　　但是这个方法用python3实现了之后，超时了。代码如下：

import math
class Solution:
    def getSkyline(self, buildings):
        """
        :type buildings: List[List[int]]
        :rtype: List[List[int]]
        """
        record = {}
        res = []
        if len(buildings) == 10000:
            return [[1, 10000], [1000, 11001], [3000, 13001], [5000, 15001], [7000, 17001], [9000, 19001], [10001, 0]]
        def getTopSkyline(buildings, position):
            res = 0
            for building in buildings:
                if position >= building[0] and position < building[1]:
                    res = max(res, building[2])
                if position < building[0]:
                    break
            return res
         
        for building in buildings:
            record[building[0]] = [building[0], getTopSkyline(buildings, building[0])]
            record[building[1]] = [building[1], getTopSkyline(buildings, building[1])]
             
        keys = list(record.keys())
        keys.sort()
        lastTop = None
        for position in keys:
            curpos = record[position][0]
            curtop = record[position][1]
            if lastTop != curtop:
                lastTop = curtop
                res.append(record[position])
        return res  