public static void sort(String[] a, int w) {
		int R = 256;
		int N = a.length;
		String[] aux = new String[N];
		for (int i = w - 1; i >= 0; i--) {
			int[] count = new int[R + 1];
			// 计算出现的频率
			for (int j = 0; j < N; j++) {
				count[a[j].charAt(i) + 1]++;
			}
			// 将频率转换为索引
			for (int k = 0; k < R; k++) {
				count[k + 1] += count[k];
				// System.out.println(count[k]);
			}
			// 将元素分类
			for (int l = 0; l < N; l++) {
				aux[count[a[l].charAt(i)]++] = a[l];
			}
			// 将元素回写
			for (int m = 0; m < N; m++) {
				a[m] = aux[m];
			}
		}
	}