Alphabetically sorting upper followed by its respective lower and everything should be in sorted manner

Question

There is no duplicates present in the input string .

Ex AbBa output = AaBb

Ex = ACdac output = AaCcd

Ex = ADaEedb output = AabDdEe

please guide me my code not run for the last test case anyone having diffrent idea please comment if lang will be c++ than it will be easy for me to understand

c++

#include<bits/stdc++.h>
using namespace std;

void swap(char *a,char *b){
char temp = *a;
*a = *b;
*b =temp;
}
int main(){
string copy1;
string s ;
cin>>s;
int j=-1;

int left = 0;
int right = s.length()-1;

while(left<right){

    if(s[left] >= 'a'  && s[right]<='z'){
        swap(&s[left],&s[right]);
        right--;
    }
    else
        left++;

}

cout<<s<<endl;
priority_queue <char, vector<char>, greater<char> > pq;
    for(int i=0;i<s.length();i++){
            if(s[i]>='A' && s[i]<='Z'){
                pq.push(s[i]);
                }
    }

    for(int i=0;i<s.length();i++){
            if(pq.empty()==false){
                char m = pq.top();
                if(find(s.begin(),s.end(),(char)(m+32))!=s.end()){
                        copy1+=(char)m;
                        copy1+=(char)(m+32);
                        pq.pop();
                    }
                else{
                copy1+=(char)m;
                pq.pop();
                }
            }
    }

cout<<copy1<<endl;

}
*/

Answer 1

A quick implementation using as much of the standard library as possible:

#include <cctype>
#include <algorithm>
#include <string>
#include <iostream>

int main(){
    auto compare = [](char a, char b){
        char upperA = std::toupper(a);
        char upperB = std::toupper(b);
        if(upperA != upperB) return upperA < upperB;
        if(upperA == a) return true;
        return false;
    };

    std::string input = "ADaEedbaaaaa";

    std::sort(input.begin(), input.end(), compare);
    auto endOfUniques = std::unique(input.begin(), input.end());
    input.erase(endOfUniques, input.end());
    std::cout << input << std::endl;
}

---

If you absolutely have to use std::priority_queue rather than std::sort, this slightly less elegant version works, although it doesn't do any de-duplication (it's not clear to me if "NO Duplicates allowed in string" is a requirement for the input or the output):

#include <cctype>
#include <string>
#include <iostream>
#include <queue>

int main(){
    struct compare{
        bool operator()(char a, char b){
            char upperA = std::toupper(a);
            char upperB = std::toupper(b);
            if(upperA != upperB) return upperA > upperB;
            if(upperA == a) return false;
            return true;
        }
    };

    std::string input = "ADaEedb";

    std::priority_queue<char, std::vector<char>, compare> queue;
    for(auto c : input) queue.push(c);

    std::string output;
    while(!queue.empty()){
        output += queue.top();
        queue.pop();
    }

    std::cout << output << std::endl;
}