CareerCup

public class Replace_aeiouSpecial {

	public static String replace(String str){
		StringBuilder sb = new StringBuilder();
		char stArr[] = str.toCharArray();
		int count=0;
		for(char c : stArr){
			sb.append(c);
			if(c=='A'||c=='E'||c=='I'||c=='O'||c=='U'||c=='a'||c=='e'||c=='i'||c=='o'||c=='u'){
				++count;
				if(count>3)
					sb.append('^');
			}
		}	
		return sb.toString();
	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		System.out.println(replace("greateribblizing"));
	}
}

private static void ReplaceVovelsByIntegers(string input)
{
List<char> vovels = new List<char>(new char[] { 'A', 'a', 'e', 'E', 'i', 'I', 'o', 'O', 'u', 'U' });
StringBuilder output = new StringBuilder();
int nVovels = 0;
foreach (char c in input)
{
if (vovels.Contains(c))
{
output.Append(c);
nVovels++;
if (nVovels > 3)
{
output.Append('^');
}
}

}
}

int main()
{
string s = "greateribblizing";
string temp ="";
string rem = s;
int count = 0;
for(int i = 0; i < rem.length(); i++)
{
if(rem[i] == 'A' ||rem[i] == 'a'||rem[i] == 'E'||rem[i] == 'e'||
rem[i] == 'I'||rem[i] == 'i'||rem[i] == 'O'||rem[i] == 'o'||
rem[i] == 'U'||rem[i] == 'u')
{
count++;
if(count < 4)
continue;
else
{
temp = temp + rem.substr(0,i+1) + "^";
rem = rem.substr(i+1);
i = 0;
}
}
}
cout<<temp+rem;


getch();
return 0;
}

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class ReplaceVowels {

	public static void main(String[] args) {
		Map<String, Boolean> vowels = new HashMap<String, Boolean>();
		vowels.put("a", true);
		vowels.put("e", true);
		vowels.put("i", true);
		vowels.put("o", true);
		vowels.put("u", true);
		vowels.put("A", true);
		vowels.put("E", true);
		vowels.put("I", true);
		vowels.put("O", true);
		vowels.put("U", true);
		Scanner terminal = new Scanner(System.in);
		String input = terminal.nextLine();
		terminal.close();

		StringBuilder output = new StringBuilder();
		for (int k = 0; k < input.length(); k++) {
			if (vowels.get(input.charAt(k) + "") != null) {
				output.append(input.charAt(k)).append("^");
			} else {
				output.append(input.charAt(k));
			}
		}

		System.out.println(output.toString());
	}
}

Output:
greateribblizing
gre^a^te^ri^bbli^zi^ng

Using map allows a constant retrieval when compared to a array for vowels list.

def letter():
a = "greateribblizing"
letters = ['a','e','i','o','u','A','E','I','O','U']
count = 0
position_last_vogal = 0
string_final = ''

for i in range(len(a)):
if a[i] in letters:
count += 1
position_last_vogal = i
if count >= 3:
break

string_final = a[:position_last_vogal+1]
for i in range(position_last_vogal+1,len(a)):
if a[i] in letters:
string_final += a[i] + "^"
else:
string_final += a[i]

return string_final

letter()

#just substitute a for raw_input

def letter():
    a = "greateribblizing"
    letters = ['a','e','i','o','u','A','E','I','O','U']
    count = 0
    position_last_vogal = 0
    string_final = ''
    
    for i in range(len(a)):
        if a[i] in letters:
            count += 1
            position_last_vogal = i 
        if count >= 3:
            break
            
    string_final = a[:position_last_vogal+1]
    for i in range(position_last_vogal+1,len(a)):
        if a[i] in letters:
            string_final += a[i] + "^"
        else:
            string_final += a[i]
    
    return string_final 
            
letter()

substitute a with raw_input