public String selectionSort(String a) {
		char[] arr = a.toCharArray();
		int minIndex;

		for (int i = 0; i < arr.length - 1; i++) {
			minIndex = i;
			for (int j = i + 1; j < arr.length; j++) {
				if (arr[j] < arr[minIndex])
					minIndex = j;
			}
			// swap
			swap(arr, minIndex, i);
		}
		return new String(arr);
	}