2611. Replace digit

Given a number n and two digits a and b. Replace every occurrence of digit a in n with digit b.

Input. Three integers n (1 ≤ n ≤ 10⁹), a, b (0 ≤ a, b ≤ 9).

Output. Print the resulting number after the replacements. Leading zeros should not be included in the output.

Sample input	Sample output
123118 1 5	523558

SOLUTION

strings

Algorithm analysis

Read the number n as a string and the digits a and b as characters. Replace all occurrences of character a in the string n with character b. Then print the resulting string, removing any leading zeros. If the final string consists only of zeros, print a single zero.

The resulting number may exceed the range of the int type. For example, if n = 1000000000 (10⁹), a = 1, b = 9, the result will be 9000000000 (9 * 10⁹).

Algorithm implementation

Store the number n as a string in the array s.

char s[100];

Read the number n as a string and the digits a and b as characters.

scanf("%s %c %c",s,&a,&b);

Replace all occurrences of character a with character b in the string s.

for (i = 0; i < strlen(s); i++)

if (s[i] == a) s[i] = b;

Convert the string s into a number res of type long long.

res = atoll(s);

Print the answer.

printf("%lld\n", res);

Algorithm implementation – string

Read the number n as a string and the digits a and b as characters.

cin >> s >> a >> b;

Replace all occurrences of character a with character b in the string s.

replace(s.begin(), s.end(), a, b);

Convert the string s into a number res of type long long.

res = stoll(s);

Print the answer.

cout << res << endl;

Java implementation

import java.util.*;

public class Main

{

public static void main(String[] args)

{

Scanner con = new Scanner(System.in);

String s = con.next();

char a = con.next().charAt(0);

char b = con.next().charAt(0);

s = s.replace(a,b);

int flag = 0;

for(int i = 0; i < s.length(); i++)

if (s.charAt(i) != '0')

{

s = s.substring(i);

flag = 1;

break;

}

if (flag == 0) s = "0";

System.out.println(s);

con.close();

}

}

Python implementation

Read the input data as strings.

s, a, b = input().split()

Replace all occurrences of character a with character b in the string s.

s = s.replace(a, b)

Convert the string s into an integer and print the result.

print(int(s))