KMP getNext()

public static int[] getNext(String pattern){
		int len = pattern.length();
		int[] next = new int[len];
		next[0] = -1;//初始化
		int index = 0;//当前位的下标
		int cur = -1;//前位的next，即next[0]
		while(index < len-1){//求解完所有的next
			if(cur == -1 || pattern.charAt(index) == pattern.charAt(cur)){//比较当前位与当前位的next所指的字符是否相等
				index++;
				cur++;//相等的话当前位的next+1作为下一位的next
				next[index] = cur;
			}
			else{
				cur = next[cur];//不相等，则找到当前位的next的next与当前位比较
			}
		}
		return next;
	}