总结：面对穷尽问题时，有的时候先排序，后面通过循环控制可达到去重的效果
def threesum(s): num=[] s.sort() for i in range(len(s)): for j in range(i+1,len(s)): for k in range(j+1,len(s)): I=[s[i],s[j],s[k]] if sum(I)==0 and I not in num: num.append(I) return num threesum([-1, 0, 1, 2, -1, -4])
