CodeSprout 官方2026/10/04 00:19

官方解答 · 置頂Java

官方解答｜標記分組尾值

CodeSprout 官方解答 · 題意分析、解題步驟與完整參考程式

import java.util.*;

public class Solution {
    private static int aggregate(List<Integer> values) {
        return values.isEmpty() ? 0 : values.get(values.size()-1);
    }
    private static class Key {
        final String label;
        final int remainder;
        Key(String label, int remainder) { this.label=label; this.remainder=remainder; }
        public boolean equals(Object other) {
            if (this == other) return true;
            if (!(other instanceof Key)) return false;
            Key key=(Key) other;
            return remainder == key.remainder && label.equals(key.label);
        }
        public int hashCode() { return Objects.hash(label,remainder); }
    }

    public static List<Integer> solve(String[] labels, int[] nums) {
        Map<Key,List<Integer>> groups = new LinkedHashMap<>();
        for (int i=0; i<nums.length; i++) {
            Key key = new Key(labels[i].toLowerCase(Locale.ROOT), Math.floorMod(nums[i],3));
            groups.computeIfAbsent(key, ignored -> new ArrayList<>()).add(nums[i]);
        }
        List<Integer> result = new ArrayList<>();
        for (List<Integer> values : groups.values()) result.add(aggregate(values));
        Collections.reverse(result);
        return result;
    }
}