« Replace character recursively

Problem

Given an input string S and two characters c1 and c2, you need to replace every occurrence of character c1 with character c2 in the given string. Do this recursively.

Input Format :

Line 1 : Input String S

Line 2 : Character c1 and c2 (separated by space)

Output Format :

Updated string

Constraints :

1 <= Length of String S <= 10^6

Sample Input :

abacd

a x

Sample Output :

xbxcd

Solution

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1#include <iostream>
2#include <iomanip>
3#include <algorithm>
4#include <string>
5#include <cstring>
6#include <vector>
7#include <cmath>
8#include <map>
9#include <climits>
10// climits for INT_MIN
11#include <unordered_map>
12using namespace std;
13
14void replaceCharacter(char input[], char c1, char c2)
15{
16    if (input[0] == '\0')
17    {
18        return;
19    }
20    if (input[0] == c1)
21    {
22        input[0] = c2;
23    }
24    replaceCharacter(input + 1, c1, c2);
25}
26int main()
27{
28    char input[1000000];
29    char c1, c2;
30    cin >> input;
31    cin >> c1 >> c2;
32    replaceCharacter(input, c1, c2);
33    cout << input << endl;
34    return 0;
35}