如何检查数组中的重复字符串

// 哈希表法示例
function findDuplicateStrings(arr) {
    const seen = new Set();
    const duplicates = new Set();
    for (const str of arr) {
        if (seen.has(str)) {
            duplicates.add(str);
        } else {
            seen.add(str);
        }
    }
    return Array.from(duplicates);
}

// 排序法示例
function findDuplicateStringsSort(arr) {
    const sortedArr = arr.slice().sort();
    const duplicates = [];
    for (let i = 1; i < sortedArr.length; i++) {
        if (sortedArr[i] === sortedArr[i - 1]) {
            if (!duplicates.includes(sortedArr[i])) {
                duplicates.push(sortedArr[i]);
            }
        }
    }
    return duplicates;
}

// 示例数组
const array = ["apple", "banana", "apple", "orange", "banana", "grape"];
console.log(findDuplicateStrings(array)); // 输出: ["apple", "banana"]
console.log(findDuplicateStringsSort(array)); // 输出: ["apple", "banana"]