public class LongestCommonPrefix {
    public String longestCommonPrefix(String[] strs) {
        // 如果字符串?dāng)?shù)組為空或長(zhǎng)度為0，返回空字符串
        if (strs == null || strs.length == 0) {
            return "";
        }
        
        // 取第一個(gè)字符串作為初始前綴
        String prefix = strs[0];
        
        // 遍歷字符串?dāng)?shù)組的其他字符串
        for (int i = 1; i < strs.length; i++) {
            // 比較當(dāng)前字符串與當(dāng)前前綴
            while (strs[i].indexOf(prefix) != 0) {
                // 縮短前綴
                prefix = prefix.substring(0, prefix.length() - 1);
                // 如果前綴為空，返回空字符串
                if (prefix.isEmpty()) {
                    return "";
                }
            }
        }
        
        // 返回最長(zhǎng)公共前綴
        return prefix;
    }

    public static void main(String[] args) {
        LongestCommonPrefix solution = new LongestCommonPrefix();
        String[] strs = {"flower", "flow", "flight"};
        System.out.println(solution.longestCommonPrefix(strs)); // 輸出 "fl"
    }
}

import java.util.HashMap;
import java.util.Map;

public class TwoSum {
    public int[] twoSum(int[] nums, int target) {
        // 創(chuàng)建哈希表用于存儲(chǔ)數(shù)值及其下標(biāo)
        Map<Integer, Integer> map = new HashMap<>();
        
        // 遍歷數(shù)組中的每個(gè)元素
        for (int i = 0; i < nums.length; i++) {
            // 計(jì)算目標(biāo)值與當(dāng)前元素的差值
            int complement = target - nums[i];
            
            // 檢查該差值是否存在于哈希表中
            if (map.containsKey(complement)) {
                // 如果存在，則返回當(dāng)前元素的下標(biāo)和該差值對(duì)應(yīng)的下標(biāo)
                return new int[] { map.get(complement), i };
            }
            
            // 將當(dāng)前元素及其下標(biāo)存入哈希表
            map.put(nums[i], i);
        }
        
        // 如果未找到符合條件的兩個(gè)數(shù)，返回空數(shù)組
        return new int[0];
    }

    public static void main(String[] args) {
        TwoSum solution = new TwoSum();
        int[] nums = {2, 7, 11, 15};
        int target = 9;
        int[] result = solution.twoSum(nums, target);
        System.out.println("Indices: [" + result[0] + ", " + result[1] + "]"); // 輸出 "Indices: [0, 1]"
    }
}