Leetcode220 error: incomparable types: int and <null>

Question

我在编译下面的代码时收到一个错误，即第 10 行 "incomparable types: int and "。

public class Solution {
public boolean containsNearbyAlmostDuplicate(int[] nums, int k, int t) {
    if (nums == null || k <= 0 || t < 0 || nums.length < 2) return false;

    TreeSet<Integer> set = new TreeSet<>();
    for (int i = 0; i < nums.length; i++) {
        int floor = set.floor(nums[i] + t);//return largest number smaller than nums[i] + t or null
        int ceil = set.ceiling(nums[i] - t);//return least number larger than num[i] - t or null

        if ((floor != null && floor >= nums[i]) || (ceil != null && ceil <= nums[i])) {
            return true;
        }

        set.add(nums[i]);

        if (set.size() > k) {
            set.remove(nums[i - k]);
        }
    }

    return false;
}}

但是如果我在treeset、floor和ceil之前加上final关键字，代码就会编译成功。谁能帮我解释一下这是怎么回事？谢谢

...
final TreeSet<Integer> set = new TreeSet<>();
for (int i = 0; i < nums.length; i++) {
    final Integer floor = set.floor(nums[i] + t);//return largest number smaller than nums[i] + t or null
    final Integer ceil = set.ceiling(nums[i] - t);//return least number larger than num[i] - t or null
...

Answer 1

int floor 将 floor 定义为基本 int 类型。 Integer floor 将 floor 定义为非平凡的 class 类型。 null 仅用于非平凡类型

Answer 2

它与 final 关键字无关（没有它也能正常工作）。您无法将原始值 (int) 与 null 进行比较。相反，您应该使用相应的对象 (Integer).

Leetcode220 error: incomparable types: int and <null>

Leetcode220 error: incomparable types: int and <null>

java

algorithm

treeset