关于leetcode 2sum、3sum、4sum到ksum的情况分析

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通过#2sum,#3sum,#4sum
推广到ksum的情况

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class Solution(object):
    
    def findKsum(self, nums, target, N, result, results):
        if len(nums) < N or N<2 or target < nums[0]*N or target>nums[-1]*N :
            return []
        if N ==2:
            l=0
            r = len(nums)-1
            while l<r:
                s = nums[l]+nums[r]
                if s == target:
                    results.append(result + [nums[l], nums[r]])
                    l +=1
                    while l<r and nums[l]==nums[l-1]:
                        l += 1
                elif s<target:
                    l+=1
                else:
                    r-=1
        else:
            for i, x in enumerate(nums[:-(N-1)]):
                if i>0 and nums[i]==nums[i-1]:
                    continue
                self.findKsum(nums[i+1:], target - x, N-1, result + [x], results)
        return results