Python/dynamic_programming/longest_sub_array.py

'''
Auther  : Yvonne

This is a pure Python implementation of Dynamic Programming solution to the longest_sub_array problem.

The problem is  :
Given an array, to find the longest and continuous sub array and get the max sum of the sub array in the given array.
'''
from __future__ import print_function


class SubArray:

    def __init__(self, arr):
        # we need a list not a string, so do something to change the type
        self.array = arr.split(',')
        print(("the input array is:", self.array))

    def solve_sub_array(self):
        rear = [int(self.array[0])]*len(self.array)
        sum_value = [int(self.array[0])]*len(self.array)
        for i in range(1, len(self.array)):
            sum_value[i] = max(int(self.array[i]) + sum_value[i-1], int(self.array[i]))
            rear[i] = max(sum_value[i], rear[i-1])
        return rear[len(self.array)-1]


if __name__ == '__main__':
    whole_array = input("please input some numbers:")
    array = SubArray(whole_array)
    re = array.solve_sub_array()
    print(("the results is:", re))