剑指offer05-06

1.替换空格

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

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;

    }