看起来并没有重复，但提示Output Limit Exceeded

3Sum.py

class Solution:
    # @return a list of lists of length 3, [[val1,val2,val3]]
    def threeSum(self, num):
        if len(num) < 3:
            return []
        threes = []
        countMap = dict()
        for i in num:
            if i in countMap:
                countMap[i] += 1
            else:
                countMap[i] = 1
        for i in range(len(num)):
            exclude = set()
            target = 0 - num[i]
            if num[i] not in countMap:
                continue
            countMap[num[i]] -= 1
            for j in range(i+1, len(num)):
                if num[j] in exclude or target - num[j] in exclude or num[j] not in countMap:
                    continue
                if countMap.get(target - num[j], 0) > 0:
                    if target == 2 * num[j] and countMap.get(num[j], 0) <= 1:
                        continue
                    exclude.add(target - num[j])
                    exclude.add(num[j])
                    threes.append(sorted([num[i], num[j], target - num[j]]))
            if num[i] in countMap:
                del countMap[num[i]]
        return threes