"Leetcode" 209. Minimum Size Subarray Sum

Minimum Size Subarray Sum

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.

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

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Credits:
Special thanks to @Freezen for adding this problem and creating all test cases.

A typical double-pointer sliding window, the front pointer expands, and the back pointer shrinks.

Record the sum of [begin, end]≥s the window size of the time.

classSolution { Public:    intMinsubarraylen (intS, vector<int>&nums) {        if(Nums.empty ())return 0; intRET =Int_max; intn =nums.size (); intBegin =0; intEnd =0; intCursum = nums[0];//guaranteed to exist         while(End <N) {//Expand             while(End < n && Cursum <s) {End++; Cursum+=Nums[end]; }            if(end = = N)//cursum of [begin, N) < s                 Break; //Shrink (cursum >= s)             while(Begin <= End && Cursum >=s) {ret= Min (ret, end-begin+1); Cursum-=Nums[begin]; Begin++; } End++; Cursum+=Nums[end]; }        if(ret = =Int_max)return 0; Else            returnret; }};

"Leetcode" 209. Minimum Size Subarray Sum