最大子数组问题

给出一个数组，要求出最大非空连续子数组，使得字数组的和最大。

参照《算法导论》，下面给出递归和非递归版本的C++实现。

template<typename T>vector<T> FindMaxCrossSubArray(const vector<T>& A, int low, int mid, int high){    T left_sum = -99999999;    T sum=0;    int max_left=mid;    for(int i=mid; i>=low; --i){        sum+=A[i];        if(sum>left_sum){            left_sum=sum;            max_left=i;        }    }    T right_sum = -99999999;    sum=0;    int max_right=mid+1;    for(int i=mid+1; i<=high; ++i){        sum+=A[i];        if(sum>right_sum){            right_sum=sum;            max_right=i;        }    }    vector<T> rst = {max_left, max_right, left_sum+right_sum};    return rst;}template<typename T>vector<T> FindMaxSubArray_reg(const vector<T>& A, int low, int high){    if(low==high){        vector<T> rst={low, high, A[low]};        return rst;    }    else{        int mid = (low+high)/2;        vector<T> rst_left = FindMaxSubArray_reg(A, low, mid);        vector<T> rst_right = FindMaxSubArray_reg(A, mid+1, high);        vector<T> rst_cross = FindMaxCrossSubArray(A, low, mid, high);        if(rst_left[2]>=rst_right[2]&&rst_left[2]>=rst_cross[2])            return rst_left;        else if(rst_right[2]>=rst_left[2]&&rst_right[2]>=rst_cross[2])            return rst_right;        else            return rst_cross;    }}template<typename T>vector<T> FindMaxSubArray(const vector<T>& A){    vector<T> tmp={0,0,A[0]};    for(int i=0; i<A.size()-1; ++i){        T left_sum=-9999999;        T sum=0;        int max_left=i;        for(int j=i+1; j>=0; --j){            sum += A[j];            if(sum>left_sum){                left_sum=sum;                max_left=j;            }        }        if(tmp[2]<left_sum){            tmp[0]=max_left;            tmp[1]=i+1;            tmp[2]=left_sum;        }    }    return tmp;}