public String insertionSort(String a) {
		char[] arr = a.toCharArray();
		char tmp;
		int j;
		for (int i = 1; i < arr.length; i++) {
			tmp = arr[i];
			j = i;
			while (j > 0 && tmp < arr[j - 1]) {
				arr[j] = arr[j - 1];
				j--;
			}
			arr[j] = tmp;

		}
		return new String(arr);
	}