难度: 中等(Medium)

题目

Given an array of n positive integers and a positive integer s, find the minimal length of a subarray of which the sum ≥ s. If there isn’t one, return 0 instead.

思路

用两个指针维护一个滑动框

For example, given the array [2,3,1,2,4,3] and s = 7,
the subarray [4,3] has the minimal length under the problem constraint.

代码

class Solution:
    # @param {integer} s
    # @param {integer[]} nums
    # @return {integer}
    def minSubArrayLen(self, s, nums):
        if nums==None or len(nums)==0:
            return 0
        i = 0
        t = 0
        min_len = 0
        for j in range(len(nums)):
            t += nums[j]
            print i,j,t
            while t >= s:
                if j-i+1 < min_len or min_len == 0:
                    min_len = j-i+1
                t -= nums[i]
                i += 1
        return min_len