Check if it is possible to convert one string into another with given constraints

• Difficulty Level : Medium
• Last Updated : 01 Aug, 2022

Given two strings contains three characters i.e ‘A’, ‘B ‘and ‘#’ only. Check is it possible to convert first string into another string by performing following operations on string first.

1. ‘A’ can move towards Left only
2. ‘B’ can move towards Right only
3. Neither ‘A’ nor ‘B’ cross each other

If it is possible then print “Yes” otherwise “No”.

Examples:

Input : str1=” #A#B#B# “, str2=” A###B#B ”
Output :Yes
Explanation :
‘A’ in str1 is right to the ‘A’ in str2 so ‘A’ of str1 can move easily towards the left because there is no ‘B’ on its left positions and for first ‘B’ in str1 is left to the ‘B’ in str2 so ‘B’ of str2 can move easily towards the right because there is no ‘A’ on its right positions and it is same for next ‘B’ so str1 can be easily converted into str2.

Input :str1=” #A#B# “, str2=” #B#A# ”
Output :No
Explanation :
Here first ‘A’ in str1 is left to the ‘A’ in str2 and according to the condition ‘A’ can’tmove towards right. so str1 can’t be converted into str2.

Method :

1. Length of Both string must be same
2. No. of A’s and B’s in both the strings must be equal
3. Order of A and B in both the strings should be same(for ex: if ‘A’ is coming before ‘B’in string second then the same sequence must be follow on string first)

Implementation:

C++

 `// C++ Program for above implementation``#include ``using` `namespace` `std;` `// Function to check is it possible to convert``// first string into another string or not.``bool` `isItPossible(string str1, string str2, ``int` `m, ``int` `n)``{` `    ``// To Check Length of Both String is Equal or Not``    ``if` `(m != n)``        ``return` `false``;` `    ``// To Check  Frequency of A's and  B's are``    ``// equal in both strings or not.``    ``if` `(count(str1.begin(), str1.end(), ``'A'``) !=``           ``count(str2.begin(), str2.end(), ``'A'``) ||``        ``count(str1.begin(), str1.end(), ``'B'``) !=``            ``count(str2.begin(), str2.end(), ``'B'``))``        ``return` `false``;` `    ``// Start traversing``    ``for` `(``int` `i = 0; i < m; i++) {``        ``if` `(str1[i] != ``'#'``) {``            ``for` `(``int` `j = 0; j < n; j++) {` `                ``// To Check no two elements cross each other.``                ``if` `((str2[j] != str1[i]) && str2[j] != ``'#'``)``                    ``return` `false``;` `                ``if` `(str2[j] == str1[i]) {``                    ``str2[j] = ``'#'``;` `                    ``// To Check Is it Possible to Move``                    ``// towards Left or not.``                    ``if` `(str1[i] == ``'A'` `&& i < j)``                        ``return` `false``;` `                    ``// To Check Is it Possible to Move``                    ``// towards Right or not.``                    ``if` `(str1[i] == ``'B'` `&& i > j)``                        ``return` `false``;` `                    ``break``;``                ``}``            ``}``        ``}``    ``}` `    ``return` `true``;``}` `// Drivers code``int` `main()``{``    ``string str1 = ``"A#B#"``;``    ``string str2 = ``"A##B"``;` `    ``int` `m = str1.length();``    ``int` `n = str2.length();` `    ``isItPossible(str1, str2, m, n) ? cout << ``"Yes\n"``                                   ``: cout << ``"No\n"``;` `    ``return` `0;``}`

Java

 `// Java Program for above implementation``class` `GFG``{` `// Function to check is it possible to convert``// first String into another String or not.``static` `boolean` `isItPossible(``char``[] str1, ``char``[] str2,``                            ``int` `m, ``int` `n)``{` `    ``// To Check Length of Both String is Equal or Not``    ``if` `(m != n)``        ``return` `false``;` `    ``// To Check Frequency of A's and B's are``    ``// equal in both Strings or not.``    ``if` `(count(str1, ``'A'``) !=``        ``count(str2, ``'A'``) ||``        ``count(str1, ``'B'``) !=``            ``count(str2, ``'B'``))``        ``return` `false``;` `    ``// Start traversing``    ``for` `(``int` `i = ``0``; i < m; i++) {``        ``if` `(str1[i] != ``'#'``) {``            ``for` `(``int` `j = ``0``; j < n; j++) {` `                ``// To Check no two elements cross each other.``                ``if` `((str2[j] != str1[i]) && str2[j] != ``'#'``)``                    ``return` `false``;` `                ``if` `(str2[j] == str1[i]) {``                    ``str2[j] = ``'#'``;` `                    ``// To Check Is it Possible to Move``                    ``// towards Left or not.``                    ``if` `(str1[i] == ``'A'` `&& i < j)``                        ``return` `false``;` `                    ``// To Check Is it Possible to Move``                    ``// towards Right or not.``                    ``if` `(str1[i] == ``'B'` `&& i > j)``                        ``return` `false``;` `                    ``break``;``                ``}``            ``}``        ``}``    ``}` `    ``return` `true``;``}` `private` `static` `int` `count(``char``[] str1, ``char` `c) {``    ``int` `count = ``0``;``    ``for``(``char` `temp : str1) {``        ``if``(c == temp)``            ``count++;``    ``}``    ``return` `count;``}` `// Drivers code``public` `static` `void` `main(String[] args)``{``    ``String str1 = ``"A#B#"``;``    ``String str2 = ``"A##B"``;` `    ``int` `m = str1.length();``    ``int` `n = str2.length();` `    ``System.out.print(isItPossible(str1.toCharArray(), str2.toCharArray(), m, n) ?``            ``"Yes\n"``:``"No\n"``);` `}``}` `// This code is contributed by Rajput-Ji`

Python3

 `# Python Program for above implementation` `# Function to check is it possible to convert``# first string into another string or not.``def` `isItPossible(str1, str2, m, n):` `    ``# To Check Length of Both String is Equal or Not``    ``if` `(m !``=` `n):``        ``return` `False` `    ``# To Check Frequency of A's and B's are``    ``# equal in both strings or not.``    ``if` `str1.count(``'A'``) !``=` `str2.count(``'A'``) \``    ``or` `str1.count(``'B'``) !``=` `str2.count(``'B'``):``        ``return` `False` `    ``# Start traversing``    ``for` `i ``in` `range``(m):``        ``if` `(str1[i] !``=` `'#'``):``            ``for` `j ``in` `range``(n):``                ``# To Check no two elements cross each other.``                ``if` `((str2[j] !``=` `str1[i]) ``and` `str2[j] !``=` `'#'``):``                    ``return` `False` `                ``if` `(str2[j] ``=``=` `str1[i]):``                    ``str2[j] ``=` `'#'` `                    ``# To Check Is it Possible to Move``                    ``# towards Left or not.``                    ``if` `(str1[i] ``=``=` `'A'` `and` `i < j):``                        ``return` `False` `                    ``# To Check Is it Possible to Move``                    ``# towards Right or not.``                    ``if` `(str1[i] ``=``=` `'B'` `and` `i > j):``                        ``return` `False` `                    ``break``                ` `    ``return` `True` `# Drivers code` `str1 ``=` `"A#B#"``str2 ``=` `"A##B"` `m ``=` `len``(str1)``n ``=` `len``(str2)` `str1 ``=` `list``(str1)``str2 ``=` `list``(str2)` `if``(isItPossible(str1, str2, m, n)):``    ``print``(``"Yes"``)``else``:``    ``print``(``"No"``)` `# This code is contributed by ankush_953`

C#

 `// C# Program for above implementation``using` `System;` `class` `GFG``{`` ` `// Function to check is it possible to convert``// first String into another String or not.``static` `bool` `isItPossible(``char``[] str1, ``char``[] str2,``                            ``int` `m, ``int` `n)``{`` ` `    ``// To Check Length of Both String is Equal or Not``    ``if` `(m != n)``        ``return` `false``;`` ` `    ``// To Check Frequency of A's and B's are``    ``// equal in both Strings or not.``    ``if` `(count(str1, ``'A'``) !=``        ``count(str2, ``'A'``) ||``        ``count(str1, ``'B'``) !=``            ``count(str2, ``'B'``))``        ``return` `false``;`` ` `    ``// Start traversing``    ``for` `(``int` `i = 0; i < m; i++) {``        ``if` `(str1[i] != ``'#'``) {``            ``for` `(``int` `j = 0; j < n; j++) {`` ` `                ``// To Check no two elements cross each other.``                ``if` `((str2[j] != str1[i]) && str2[j] != ``'#'``)``                    ``return` `false``;`` ` `                ``if` `(str2[j] == str1[i]) {``                    ``str2[j] = ``'#'``;`` ` `                    ``// To Check Is it Possible to Move``                    ``// towards Left or not.``                    ``if` `(str1[i] == ``'A'` `&& i < j)``                        ``return` `false``;`` ` `                    ``// To Check Is it Possible to Move``                    ``// towards Right or not.``                    ``if` `(str1[i] == ``'B'` `&& i > j)``                        ``return` `false``;`` ` `                    ``break``;``                ``}``            ``}``        ``}``    ``}`` ` `    ``return` `true``;``}`` ` `private` `static` `int` `count(``char``[] str1, ``char` `c) {``    ``int` `count = 0;``    ``foreach``(``char` `temp ``in` `str1) {``        ``if``(c == temp)``            ``count++;``    ``}``    ``return` `count;``}`` ` `// Drivers code``public` `static` `void` `Main(String[] args)``{``    ``String str1 = ``"A#B#"``;``    ``String str2 = ``"A##B"``;`` ` `    ``int` `m = str1.Length;``    ``int` `n = str2.Length;`` ` `    ``Console.Write(isItPossible(str1.ToCharArray(), str2.ToCharArray(), m, n) ?``            ``"Yes\n"``:``"No\n"``);`` ` `}``}` `// This code is contributed by Rajput-Ji`

Javascript

 ``

Output

`Yes`

Time Complexity : O(n*m)
Auxiliary Space: O(n+m)

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