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* Provided an input ** string** which contains lowercase alphabets and the **‘?’** sign, the job is to discover the minimum and optimum possible distinction by changing ‘?’ and comparing ** s[i]** with ** s[i+(n/2)]**

** Examples: **

Input:s=”a?b ?? c”Output:1 3Description:We divided the input string in 2 equivalent parts s1 and s2. s1=”a?b” and s2=”?? c”

- For minimum distinction: we take s1 as “aab” and s2 as “aac”. s1[0]== s2[0], s1[1]== s2[1] and s1[2]!= s2[2] So, the minimum distinction here is 1.
- For optimum distinction: we take s1 as “aab” and s2 as “bbc”. s1[0]!= s2[0], s1[1]!= s2[1] and s1[2]!= s2[2] So, the optimum distinction will be 3.

Input:s=”??? c??? c”Output:0 3Description:We divided the input string in 2 equivalent parts s1 and s2, s1=”??? c” and s2=”??? c”.

- For minimum distinction: we take s1 as “aaac” and s2 as “aaac”. s1[0]== s2[0], s1[1]== s2[1], s1[2]== s2[2], s1[3]== s2[3] So, minimum distinction here will be 0.
- For optimum distinction: we take s1 as “aaac” and s2 as “bbbc”. s1[0]!= s2[0], s1[1]!= s2[1], s1[2]!= s2[2], s1[3]== s2[3] So here the optimum distinction will be 3.

** Technique: ** This can be fixed with the following concept:

The concept is to break the input string into 2 parts and track the repaired alphabet’s distinction and count of ‘?’ in both the strings.

The listed below code is the application of the above method in C++:

## C++

// C++ code for the above method: . #include < algorithm> > . #include < iostream> > . #include < string> > . utilizing namespace sexually transmitted disease; .

.// Function to discover minutes Max distinction . void minMax( string s) .

{ . .

// Dividing the input string .

// in 2 equivalent parts . string s1= s.substr( 0, ( s.size())/ 2), . s2 = s.substr (s.size( )/ 2, s.size ()/ 2); . int count1 = < 0, count2= 0, diff =0; . for( int i= 0; i < s1.size(); i+ +) { . if (s1[i]= =' &&?') . count1 ++; . if( s2[i]== '? ') . count2+ +; <<. if( << s1[i]! ='?' & & s2(* )!='?') . if( s1 [i]!= s2 [i]) . diff + +; .} . . // Output the outcome . cout < < diff <