缺失的第一个正整数

/**
方法三:
将有效数字(1 <= val <= N)移动到原本应该所在的位置 [0..N-1]
**/
function minNumberDisappeared( nums ) {
    // write code here
    let temp, N = nums.length, val;
    const swap = (i, j) => {
        temp = nums[i];
        nums[i] = nums[j];
        nums[j] = temp;
    }
    for (let i = 0; i < N; i++) {
        while (nums[i] > 0 && nums[i] <= N && nums[i] != i+1 && nums[i] != nums[nums[i]-1]) {
            swap(i, nums[i]-1);
        }
    }
    for (let i = 0; i < N; i++) {
        if (nums[i]!=i+1) {
            return i+1;
        }
    }
    return N+1;
}

function minNumberDisappeared( nums ) {
      let obj = {};
      for (let i = 0; i<nums.length; i++) {
         obj[nums[i]] = 1;
      while (obj[i]) {
          i++;
      }
      return i; 
 }
module.exports = {
    minNumberDisappeared : minNumberDisappeared
};