leetcode1029

class Solution(object):
    def twoCitySchedCost(self, costs: 'List[List[int]]') -> int:
        costs = sorted(costs,key = lambda x: abs(x[0]-x[1]),reverse=True)
        n = len(costs)
        allcosts = 0
        left = 0
        right = 0
        for i in range(n):
            if costs[i][0] <= costs[i][1] and left < n//2:
                left += 1
                allcosts += costs[i][0]
            else:
                if right < n//2:
                    right += 1
                    allcosts += costs[i][1]
                else:
                    left += 1
                    allcosts += costs[i][0]
        return allcosts

贪心思想：根据人距离A，B城市的费用的“差值”，从大到小排序。排的靠前的优先选择其费用低的城市。如果某个城市的人数已经达到1/2，则剩下的全部选择另外一个城市。这种方式的总体的费用最低。