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80 lines
2.1 KiB
Python
80 lines
2.1 KiB
Python
"""
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author : Mayank Kumar Jha (mk9440)
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"""
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from typing import List
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import time
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import matplotlib.pyplot as plt
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from random import randint
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def find_max_sub_array(A,low,high):
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if low==high:
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return low,high,A[low]
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else :
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mid=(low+high)//2
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left_low,left_high,left_sum=find_max_sub_array(A,low,mid)
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right_low,right_high,right_sum=find_max_sub_array(A,mid+1,high)
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cross_left,cross_right,cross_sum=find_max_cross_sum(A,low,mid,high)
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if left_sum>=right_sum and left_sum>=cross_sum:
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return left_low,left_high,left_sum
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elif right_sum>=left_sum and right_sum>=cross_sum :
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return right_low,right_high,right_sum
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else:
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return cross_left,cross_right,cross_sum
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def find_max_cross_sum(A,low,mid,high):
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left_sum,max_left=-999999999,-1
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right_sum,max_right=-999999999,-1
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summ=0
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for i in range(mid,low-1,-1):
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summ+=A[i]
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if summ > left_sum:
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left_sum=summ
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max_left=i
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summ=0
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for i in range(mid+1,high+1):
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summ+=A[i]
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if summ > right_sum:
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right_sum=summ
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max_right=i
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return max_left,max_right,(left_sum+right_sum)
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def max_sub_array(nums: List[int]) -> int:
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"""
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Finds the contiguous subarray (can be empty array)
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which has the largest sum and return its sum.
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>>> max_sub_array([-2,1,-3,4,-1,2,1,-5,4])
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6
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>>> max_sub_array([])
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0
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>>> max_sub_array([-1,-2,-3])
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0
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"""
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best = 0
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current = 0
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for i in nums:
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current += i
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if current < 0:
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current = 0
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best = max(best, current)
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return best
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if __name__=='__main__':
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inputs=[10,100,1000,10000,50000,100000,200000,300000,400000,500000]
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tim=[]
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for i in inputs:
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li=[randint(1,i) for j in range(i)]
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strt=time.time()
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(find_max_sub_array(li,0,len(li)-1))
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end=time.time()
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tim.append(end-strt)
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print("No of Inputs Time Taken")
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for i in range(len(inputs)):
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print(inputs[i],'\t\t',tim[i])
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plt.plot(inputs,tim)
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plt.xlabel("Number of Inputs");plt.ylabel("Time taken in seconds ")
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plt.show()
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