The shortest editing distance calculation method implemented by Ruby, And the ruby Calculation Method

The shortest editing distance calculation method implemented by Ruby, And the ruby Calculation Method

The dynamic planning algorithm is used to calculate the shortest editing distance.

Copy codeThe Code is as follows:
# Encoding: UTF-8
# Author: xu jin
# Date: Nov 12,201 2
# EditDistance
# To find the minimum cost by using EditDistance algorithm
# Example output:
# "Please input a string :"
# Exponential
# "Please input the other string :"
# Polynomial
# "The expected cost is 6"
# The result is:
# ["E", "x", "p", "o", "n", "e", "n", "-", "t ", "I", "a", "l"]
# ["-", "-", "P", "o", "l", "y", "n", "o", "m ", "I", "a", "l"]

P "Please input a string :"
X = gets. chop. chars. map {| c}
P "Please input the other string :"
Y = gets. chop. chars. map {| c}
X. unshift ("")
Y. unshift ("")
E = Array. new (x. size) {Array. new (y. size )}
Flag = Array. new (x. size) {Array. new (y. size )}
DEL, INS, CHA, FIT = (1 .. 4). to_a # deleat, insert, change, and fit
 
Def edit_distance (x, y, e, flag)
(0. x. length-1). each {| I | e [I] [0] = I}
(0 .. y. length-1). each {| j | e [0] [j] = j}
Diff = Array. new (x. size) {Array. new (y. size )}
For I in (1. x. length-1) do
For j in (1 .. y. length-1) do
Diff [I] [j] = (x [I] = y [j])? 0: 1
E [I] [j] = [e [I-1] [j] + 1, e [I] [j-1] + 1, e [I-1] [j-1] + diff [I] [j]. min
If e [I] [j] = e [I-1] [j] + 1
Flag [I] [j] = DEL
Elsif e [I] [j] = e [I-1] [j-1] + 1
Flag [I] [j] = CHA
Elsif e [I] [j] = e [I] [j-1] + 1
Flag [I] [j] = INS
Else flag [I] [j] = FIT
End
End
End
End

Out_x, out_y = [], []

Def solution_structure (x, y, flag, I, j, out_x, out_y)
Case flag [I] [j]
When FIT
Out_x.unshift (x [I])
Out_y.unshift (y [j])
Solution_structure (x, y, flag, I-1, j-1, out_x, out_y)
When DEL
Out_x.unshift (x [I])
Out_y.unshift ('-')
Solution_structure (x, y, flag, I-1, j, out_x, out_y)
When INS
Out_x.unshift ('-')
Out_y.unshift (y [j])
Solution_structure (x, y, flag, I, j-1, out_x, out_y)
When CHA
Out_x.unshift (x [I])
Out_y.unshift (y [j])
Solution_structure (x, y, flag, I-1, j-1, out_x, out_y)
End
# If flag [I] [j] = nil, go here
Return if I = 0 & j = 0
If j = 0
Out_y.unshift ('-')
Out_x.unshift (x [I])
Solution_structure (x, y, flag, I-1, j, out_x, out_y)
Elsif I = 0
Out_x.unshift ('-')
Out_y.unshift (y [j])
Solution_structure (x, y, flag, I, j-1, out_x, out_y)
End
End

Edit_distance (x, y, e, flag)
P "The expected edit distance is # {e [x. length-1] [y. length-1]}"
Solution_structure (x, y, flag, x. length-1, y. length-1, out_x, out_y)
Puts "The result is: \ n # {out_x} \ n # {out_y }"