筆試編程題彙總(8)

"""
給定一個最大數據，找出具有最大和的連續子串，返回其和，時間複雜度儘量低
input: 
    -2, 2, -3, 4, -1, 2, 1, -5, 3
output:
    6

解釋:子串爲[4,-1,2,1]
"""
import sys

def get_max_sub_sum(data):
    if len(data)==0:
        return 0
    if len(data)==1:
        return data[0]

    # data_accum[n] = sum(data[:n])
    data_accum = [0]*len(data)
    data_accum[0] = data[0]
    for idx, data_temp in enumerate(data[1:]):
        data_accum[1+idx] = data_accum[idx]+data_temp

    # max(data_accum[j]-data_accum[i]) for i in range(len(data)) for j in range(len(data)) if j>i
    sub_sum = [data_accum[j]-data_accum[i] for i in range(len(data)) for j in range(len(data)) if j>i]
    return max(sub_sum)
    

if __name__=="__main__":
    line1 = sys.stdin.readline().strip()
    data = list(map(int, line1.split(", ")))
    # data = [-2, 2, -3, 4, -1, 2, 1, -5, 3]
    print(get_max_sub_sum(data))