【leetcode】757. Set Intersection Size At Least Two

题目如下：

解题思路：贪心算法。首先把intervals按第二个元素从小到大排序，然后遍历intervals,如果集合S和intervals[i]没有交集，那么把intervals[i]的最大值和次大值加入集合S；如果交集只有一个元素，则把最大值加入S。

代码如下：

class Solution(object):
    def intersectionSizeTwo(self, intervals):
        """
        :type intervals: List[List[int]]
        :rtype: int
        """
        import bisect
        def cmpf(l1,l2):
            if l1[1] != l2[1]:
                return l1[1] - l2[1]
            return l2[0] - l1[0]
        intervals.sort(cmp=cmpf)
        res = None
        for low,high in intervals:
            if low == 29 and high == 37:
                pass
            if res == None:
                res = [high-1,high]
            elif res[-1] < low:
                #res[1] = low + 1
                res.append(high-1)
                res.append(high)
            elif res[-1] == low:
                res.append(high)
            elif bisect.bisect_right(res,high) -  bisect.bisect_left(res,low)  == 1:
                res.append(high)
            #print res
        #print intervals
        #print res
        return len(res)