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Program to find number of ways we can concatenate words to make palindromes in Python
Suppose we have a list of distinct words, we have to find the number of different ways we can concatenate two different words from the given list of words to make a palindrome.
So, if the input is like words = ["time", "emit", "mo", "m"], then the output will be 3, as we can make "timeemit", "emittime", and "mom".
To solve this, we will follow these steps −
res := 0
ln := number of words in the array
for k in range 0 to 1, do
for i in range 0 to ln − 1, do
for j in range i + 1 to ln − 1, do
res := res + (1 when words[i] concatenate words[j] is palindrome, otherwise 0)
words := words in reverse order
return res
Let us see the following implementation to get better understanding −
Example
class Solution: def solve(self, words): def is_palindrome(w1, w2): w3 = w1 + w2 return w3 == w3[::−1] res = 0 ln = len(words) for k in range(2): for i in range(ln): for j in range(i + 1, ln): res += is_palindrome(words[i], words[j]) words = words[::−1] return res ob = Solution() words = ["time", "emit", "mo", "m"] print(ob.solve(words))
Input
["time", "emit", "mo", "m"]
Output
3
Updated on: 15-Dec-2020
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