Finds and returns the longest sequence of consecutive characters (as per ASCII) in given string.

LongestCharSeq.java

public class LongestCharSeq {

	public String findLongest(String s) {
		StringBuffer result = new StringBuffer();
		s.toLowerCase();
		
		int lastChar = getAsciiVal(s.charAt(0)) - 1;
		
		StringBuffer currentSeq = new StringBuffer();
		for(int i = 0; i<s.length(); i++) {
			int currChar = (int) s.charAt(i);
			
			if(currChar == lastChar + 1) {
				currentSeq.append(s.charAt(i));
			} else {
				if(currentSeq.length() > result.length() && currentSeq.length() > 1) {
					result = currentSeq;
				}
				
				currentSeq = new StringBuffer();
			}
			
			lastChar = currChar;
		}
		
		if(currentSeq.length() > result.length() && currentSeq.length() > 1) result = currentSeq;
		
		return result.toString();
	}
	
	public int getAsciiVal(char c) {
		return (int) c;
	}
}