mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-10-06 13:49:30 +00:00
76 lines
2.1 KiB
Python
76 lines
2.1 KiB
Python
"""
|
|
Author : Turfa Auliarachman
|
|
Date : October 12, 2016
|
|
|
|
This is a pure Python implementation of Dynamic Programming solution to the edit distance problem.
|
|
|
|
The problem is :
|
|
Given two strings A and B. Find the minimum number of operations to string B such that A = B. The permitted operations are removal, insertion, and substitution.
|
|
"""
|
|
from __future__ import print_function
|
|
|
|
|
|
class EditDistance:
|
|
"""
|
|
Use :
|
|
solver = EditDistance()
|
|
editDistanceResult = solver.solve(firstString, secondString)
|
|
"""
|
|
|
|
def __init__(self):
|
|
self.__prepare__()
|
|
|
|
def __prepare__(self, N = 0, M = 0):
|
|
self.dp = [[-1 for y in range(0,M)] for x in range(0,N)]
|
|
|
|
def __solveDP(self, x, y):
|
|
if (x==-1):
|
|
return y+1
|
|
elif (y==-1):
|
|
return x+1
|
|
elif (self.dp[x][y]>-1):
|
|
return self.dp[x][y]
|
|
else:
|
|
if (self.A[x]==self.B[y]):
|
|
self.dp[x][y] = self.__solveDP(x-1,y-1)
|
|
else:
|
|
self.dp[x][y] = 1+min(self.__solveDP(x,y-1), self.__solveDP(x-1,y), self.__solveDP(x-1,y-1))
|
|
|
|
return self.dp[x][y]
|
|
|
|
def solve(self, A, B):
|
|
if isinstance(A,bytes):
|
|
A = A.decode('ascii')
|
|
|
|
if isinstance(B,bytes):
|
|
B = B.decode('ascii')
|
|
|
|
self.A = str(A)
|
|
self.B = str(B)
|
|
|
|
self.__prepare__(len(A), len(B))
|
|
|
|
return self.__solveDP(len(A)-1, len(B)-1)
|
|
|
|
if __name__ == '__main__':
|
|
try:
|
|
raw_input # Python 2
|
|
except NameError:
|
|
raw_input = input # Python 3
|
|
|
|
solver = EditDistance()
|
|
|
|
print("****************** Testing Edit Distance DP Algorithm ******************")
|
|
print()
|
|
|
|
print("Enter the first string: ", end="")
|
|
S1 = raw_input().strip()
|
|
|
|
print("Enter the second string: ", end="")
|
|
S2 = raw_input().strip()
|
|
|
|
print()
|
|
print("The minimum Edit Distance is: %d" % (solver.solve(S1, S2)))
|
|
print()
|
|
print("*************** End of Testing Edit Distance DP Algorithm ***************")
|