js list判断是否重复

function hasDuplicates(array) {
  return new Set(array).size !== array.length;
}

// 示例
const list = [1, 2, 3, 4, 5, 3];
console.log(hasDuplicates(list)); // 输出: true

function hasDuplicates(array) {
  const seen = {};
  for (let i = 0; i < array.length; i++) {
    if (seen[array[i]]) {
      return true;
    }
    seen[array[i]] = true;
  }
  return false;
}

// 或者使用 Map
function hasDuplicates(array) {
  const seen = new Map();
  for (const item of array) {
    if (seen.has(item)) {
      return true;
    }
    seen.set(item, true);
  }
  return false;
}

// 示例
const list = [1, 2, 3, 4, 5, 3];
console.log(hasDuplicates(list)); // 输出: true

function hasDuplicates(array) {
  const sorted = array.slice().sort(); // 使用 slice() 复制数组，避免修改原数组
  for (let i = 1; i < sorted.length; i++) {
    if (sorted[i] === sorted[i - 1]) {
      return true;
    }
  }
  return false;
}

// 示例
const list = [1, 2, 3, 4, 5, 3];
console.log(hasDuplicates(list)); // 输出: true

function hasDuplicates(array) {
  const seen = new Set();
  for (const item of array) {
    const serialized = JSON.stringify(item);
    if (seen.has(serialized)) {
      return true;
    }
    seen.add(serialized);
  }
  return false;
}

// 示例
const list = [{a:1}, {a:1}, {b:2}];
console.log(hasDuplicates(list)); // 输出: true