当A的所有数组均为负数时，FIND-MAXIMUM-SUBARRAY返回什么？
FIND-MAXIMUN-SUBARRAY(A, low, high) if high == low return(low, high, A[low]) else mid = (low + high) / 2 (left_low, left_high, left_sum) = FIND-MAXIMUN-SUBARRAY(A, low, mid) (rihgt_low, rihgt_high, rihgt_sum) = FIND-MAXIMUN-SUBARRAY(A, mid + 1, high) (cross_low, cross_high, cross_sum) = FIND-MAX-CROSSING-SUBARRAY(A, low, mid, high) if left_sum >= right_sum and left_sum >= cross_sum return(left_low, left_high, left_sum) elseif right_sum >= left_sum and right_sum >= cross_sum return(right_low, right_high, right_sum) else return(cross_low, cross_high, cross_sum)
