# return a list of lists of length 3   
def three_Sum(num):  
    if len(num)<3: return []  
    num.sort()  
    result=[]  
    for i in range(len(num)-2):  
        left=i+1  
        right=len(num)-1  
        if i!=0 and num[i]==num[i-1]:continue  
        while left<right:  
            if num[left]+num[right]==-num[i]:  
                result.append([num[i],num[left],num[right]])  
                left=left+1  
                right=right-1  
                while num[left]==num[left-1] and left<right:left=left+1  
                while num[right]==num[right+1] and left<right: right=right-1  
            elif num[left]+num[right]<-num[i]:  
                left=left+1  
            else:  
                right=right-1  
    return result  
   
nums1=[-1,0,1,2,-1,-4]  
nums2 = [-25,-10,-7,-3,2,4,8,10]  
print(three_Sum(nums1))  
print(three_Sum(nums2))