/**
 *
 * @author: Andrei_Misan
 */
public class StringTask {

	public static void main(String[] args) {
		String arrStr = "aaabbbbbaa";
		int k = 1;
		int res = calculate(arrStr, k);
		System.out.println("result = " + res);
	}

	public static int calculate(String pArrStr, int pK) {
		int diffPos=0;
		int res = 0;
		char[] arr = pArrStr.toCharArray();

		//initial values for first run
		int[] data = new int[]{-1,0};

		while (data[1] > diffPos || data[0] == -1 ){
			diffPos = data[1];
			data = attemptIterate(pK, data[1], arr);
			if(data[0] > res){
				res = data[0];
			}
		}
		return res;
	}

	private static int[] attemptIterate(int pK, int pDiffPos, char[] pArr) {
		int cursor = pDiffPos;
		int counter = 0 ;
		int curCode = -1;
		int tempK = pK;
		while(cursor < pArr.length){
			if(curCode == -1){
				curCode = pArr[pDiffPos];
				counter++;
			} else if(curCode == pArr[cursor]){
				counter++;
			}else{
				if(tempK == 0){
					break;
				}
				if(tempK == pK){
					pDiffPos = cursor;
				}
				tempK--;
				counter++;
			}
			cursor++;
		}
		return new int[]{counter, pDiffPos};
	}
}