StringCompressed.java

public static String compressString(String originalString) {
	if(originalString.length()<3) return originalString;
	int freq = 1; //default value for the frequency is 1 to signal that we have seen atleast this character we tokinig abotu
	StringBuilder compressedString = new StringBuilder();// we will build the answer here
	int current_index = 1;
	for (; current_index < originalString.length(); ++current_index) {
	    if (originalString.charAt(current_index - 1) == originalString.charAt(current_index)) {
		++freq;
	    } else {//if they are not equal
		compressedString.append(originalString.charAt(current_index - 1)).append(freq);
		freq = 1;//to indicate we have seen the character at this index
	    }
	}
	compressedString.append(originalString.charAt(current_index-1)).append(freq);
	return (compressedString.length() < originalString.length()) ? compressedString.toString() : originalString;
}