2022/08/23荣耀通用软件开发笔试
这次题目感觉比较简单,都是常规题,所以都AC了(本渣渣碰到难一点的就全跪了...)
第一题就是用哈希表统计次数,然后将最高频对于单词收集起来,进行排序,取第一个
package honor1; import java.util.*; public class Main { public static void main(String[] args) { Scanner cin = new Scanner(System.in); String line = cin.nextLine(); String[] votes = line.split(","); Map<String, Integer> counts = new HashMap<>(); int maxVote = 0; for (String name : votes) { if (!check(name)) { System.out.println("error.0001"); return; } int vote = counts.getOrDefault(name, 0) + 1; counts.put(name, vote); maxVote = Math.max(maxVote, vote); } List<String> names = new ArrayList<>(); for (Map.Entry<String, Integer> entry : counts.entrySet()) { String key = entry.getKey(); int value = entry.getValue(); if (value == maxVote) { names.add(key); } } Collections.sort(names); System.out.println(names.get(0)); cin.close(); } public static boolean check(String name) { int len = name.length(); for (int i = 0; i < len; i++) { char ch = name.charAt(i); if (!Character.isLetter(ch)) return false; if (i == 0) { if (!Character.isUpperCase(ch)) return false; } else { if (!Character.isLowerCase(ch)) return false; } } return true; } }第二题用的库函数,直接将输入解释为BigInteger,然后用toString()方法转化为各种进制表示,再判断是否是回文串
package honor2; import java.math.BigInteger; import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner cin = new Scanner(System.in); String line = cin.nextLine(); BigInteger n = new BigInteger(line, 10); boolean hasAnswer = false; for (int radix = 2; radix <= 16; radix++) { String nums = n.toString(radix); if (isPalindrome(nums)) { hasAnswer = true; System.out.println(radix); } } if (!hasAnswer) System.out.println(-1); } public static boolean isPalindrome(String nums) { int lo = 0, hi = nums.length() - 1; while (lo < hi) { char a = nums.charAt(lo); char b = nums.charAt(hi); if (a != b) return false; lo++; hi--; } return true; } }
第三题就是一致性哈希,代码写的烂,就不放了,主要讲下思路。可以用考虑用TreeMap保存所有存活redis节点,宕机理解为从TreeMap中删除相应redis节点,然后直接用ceiling(hash(token))找大于等于hash(token)的第一个节点,若没有找到,说明被分配到TreeMap中的第一个节点。
还是贴下代码吧,好多冗余代码,也没设计好,轻喷...
package honor3; import java.util.HashMap; import java.util.Map; import java.util.Scanner; import java.util.TreeMap; public class Main { static Map<String, Integer> redisNum = new HashMap<>(); static Map<String, Integer> addRedisNum = new HashMap<>(); public static void main(String[] args) { Scanner cin = new Scanner(System.in); String line = cin.nextLine(); String[] strs = line.split(":"); char command = strs[0].charAt(0); String content = strs[1]; // System.out.println(command + ":" + content); TreeMap<Integer, RedisNode> cluster = getCluster(); switch (command) { case '1': System.out.println(getNumber(content)); break; case '2': System.out.println(getTokenBelongNum(cluster, hash(content))); break; case '3': System.out.println(getNumberWithDownServer(cluster, content)); break; case '4': System.out.println(getNumber(content)); break; case '5': System.out.println(afterInsertRedis(cluster, content)); break; } cin.close(); } public static int getNumberWithDownServer(TreeMap<Integer, RedisNode> cluster, String content) { String[] parts = content.split(";"); String servers = parts[0], token = parts[1]; String[] nodes = servers.split(","); for (String node : nodes) { int number = getNumber(node); // System.out.println(number); cluster.remove(number); } // System.out.println(cluster.size()); return getTokenBelongNum(cluster, hash(token)); } public static int getNumber(String nodeName){ return nodeName.startsWith("add") ? addRedisNum.get(nodeName) : redisNum.get(nodeName); } public static TreeMap getCluster() { TreeMap<Integer, RedisNode> cluster = new TreeMap<>(); for (int i = 1; i <= 20; i++) { int number = (i - 1) * 50; String name = "redis_" + (i < 10 ? "0" + i : String.valueOf(i)); RedisNode node = new RedisNode(name, number, true); cluster.put(number, node); redisNum.put(name, number); String addName = "add_" + name; int addNum = 25 + (i - 1) / 2 * 50 + (i % 2 == 1 ? 0 : 500); addRedisNum.put(addName, addNum); } return cluster; } public static int afterInsertRedis(TreeMap<Integer, RedisNode> cluster, String content) { String[] parts = content.split(";"); String server = parts[0], token = parts[1]; String[] words = server.split("_"); int num = Integer.parseInt(words[2]); for (int i = 1; i <= num; i++) { String addName = getAddRedisName(i); int addNum = addRedisNum.get(addName); RedisNode node = new RedisNode(addName, addNum, true); // System.out.println(node); cluster.put(addNum, node); } // System.out.println(cluster.size()); return getTokenBelongNum(cluster, hash(token)); } public static int getTokenBelongNum(TreeMap<Integer, RedisNode> cluster, int hashCode) { // int hashCode = hash(token); Integer number = cluster.ceilingKey(hashCode); if (number == null) { return cluster.firstKey(); } return number; } public static int hash(String token) { int sum = 0; for (char ch : token.toCharArray()) { sum += ch; } return sum % 999; } public static String getAddRedisName(int i) { String name = "redis_" + (i < 10 ? "0" + i : String.valueOf(i)); String addName = "add_" + name; return addName; } } class RedisNode { String name; int number; // 没用上 boolean isOnLine; public RedisNode(String name, int number, boolean isOnLine) { this.name = name; this.number = number; this.isOnLine = isOnLine; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getNumber() { return number; } public void setNumber(int number) { this.number = number; } public boolean isOnLine() { return isOnLine; } public void setOnLine(boolean onLine) { isOnLine = onLine; } @Override public String toString() { return "RedisNode{" + "name='" + name + '\'' + ", number=" + number + ", isOnLine=" + isOnLine + '}'; } }