剑指offer05-06

1 public static String replaceSpace(String s){
2         StringBuilder stringBuilder = new StringBuilder();
3         for (int i = 0; i < s.length(); i++) {
4             if(s.charAt(i) == ' ') stringBuilder.append("%20");
5             else stringBuilder.append(s.charAt(i));
6         }
7         return stringBuilder.toString();
8     }

2.从尾到头打印链表

public static int[] reversePrintPlus(ListNode head){
        int len = 0;
        ListNode cur = head;
        while(cur != null){
            len++;
            cur = cur.next;
        }
        int [] res = new int[len];
        while(head != null && len > 0){
            res[len-1] = head.val;
            head = head.next;
            len--;
        }
        return res;

    }

知之为知之，不知为不知