shopee虾皮笔经

shoppe虾皮研发岗秋招第四批
一、15道选择题做的一塌糊涂

主要包括kafka、进程通信、TCP、概率题、redis等

二、编程题

1、找出没出现的最小正整数

2、判断链表是否回文

3、字符串数组，每个元素包含“姓名，交易额，时间、城市”，要求挑出交易额大于1000和姓名相同城市不同并且交易额差<=60的元素

/*
第一题
 */
public class Solution {
    /**
     *
     * @param nums int整型一维数组 入参数组
     * @return int整型
     */
    public int firstMissingPositive (int[] nums) {
        // write code here
        Arrays.sort(nums);
        int i =0;
        while(i<nums.length){
            if (nums[i]>0) break;
            else i++;
        }
        if (i==nums.length||nums[i]!=1) return 1;
        int now = 1;
        for(;i<nums.length;i++){
            if (nums[i]==now){
                now++;
            }else{
                return now;
            }
        }
        return now;
    }
}

/*
第二题
 */
/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     *
     * @param pHead ListNode类
     * @return bool布尔型
     */
    public boolean isPalindrome (ListNode pHead) {
        // write code here
        //先截断
        ListNode slow = pHead;
        ListNode fast = pHead;
        while(fast!=null&&fast.next!=null){
            slow = slow.next;
            fast = fast.next.next;
        }
        //再反转
        ListNode res ;
        if (fast==null){
            res = reverse(slow);
        }else{
            res = reverse(slow.next);
        }
        //最后判断
        while(res!=null){
            if (res.val!=pHead.val) return false;
            res = res.next;
        }
        return true;
    }

    public ListNode reverse(ListNode head){
        ListNode p = null;
        ListNode q = head;
        while(q!=null){
            ListNode flag = q.next;
            q.next = p;

            p = q;
            q = flag;
        }
        return p;
    }
}


/*
第三题
 */

public class Solution {
    /**
     *
     * @param vTransaction string字符串一维数组
     * @return string字符串一维数组
     */
    public String[] invalidTransaction (String[] vTransaction) {
        // write code here
        String[] res = new String[vTransaction.length];
        int count = 0;
        HashSet<String> data = new HashSet<>();
        List<List<String>> list= new ArrayList<>();
        for(int i=0;i<vTransaction.length;i++){
            String[] now = vTransaction[i].split(",");
            int money = Integer.valueOf(now[2]);
            if (money>1000){
                res[count] = vTransaction[i];
                count++;
                continue;
            }

            if (data.contains(now[0])){
                for(int j=0;j<list.size();){
                    if (list.get(j).get(0).equals(now[0])){
                        int nowTime = Integer.valueOf(now[1]);
                        String[] in = list.get(j).get(1).split(",");
                        int inTime = Integer.valueOf(in[1]);
                        String insite = in[3];
                        if (!now[3].equals(insite)&&Math.abs(inTime-nowTime)<=60){
                            res[count] = list.get(j).get(1);
                            count++;
                            res[count] = vTransaction[i];
                            count++;
                            list.remove(j);
                        }
                    }else{
                        j++;
                    }
                }
            }else{
                List<String> flag = new ArrayList<>();
                flag.add(now[0]);
                flag.add(vTransaction[i]);
                list.add(flag);
                data.add(now[0]);
            }

        }
        return Arrays.copyOf(res,count);
    }
}