Syntax error Program to check whether final string can be formed using other two strings or not in Python

Program to check whether final string can be formed using other two strings or not in Python

Suppose we have two strings s, t, and another string r we have to check whether there is any way to get r by merging characters in order from s and t.

So, if the input is like s = "xyz" t = "mno" r = "xymnoz", then the output will be True, as xymnoz can be formed by interleaving xyz and mno.

To solve this, we will follow these steps −

  • Define a function solve() . This will take s, t, r

  • if s, t and r are empty, then

    • return True

      • if r is empty, then

        • return False

  • if s is empty, then

    • return true when t is same as r, otherwise false

  • if not t is non−zero, then

    • return s is same as r

  • if s[0] is same as r[0], then

    • if solve(s[from index 1 to end], t, r[from index 1 to end]) is true, then

      • return True

  • if t[0] is same as r[0], then

    • if solve(s, t[from index 1 to end], r[from index 1 to end]) is true, then

      • return True

  • return False

Let us see the following implementation to get better understanding −

Example

 Live Demo

class Solution:
   def solve(self, s, t, r):
      if not s and not t and not r:
         return True
      if not r:
         return False
      if not s:
         return t == r
      if not t:
         return s == r
      if s[0] == r[0]:
         if self.solve(s[1:], t, r[1:]):
            return True
         if t[0] == r[0]:
            if self.solve(s, t[1:], r[1:]):
               return True
         return False
ob = Solution()
s = "xyz"
t = "mno"
r = "xymnoz"
print(ob.solve(s, t, r))

Input

"xyz", "mno", "xymnoz"

Output

True
Updated on: 2020-12-26T10:38:50+05:30

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