关于leetcode 239 ,一个很奇怪的问题

下面两份代码仅仅是Integer 改为了 int，为什么一个答案错误，一个正确     

错误的答案

class Solution {

    class MyQue {
        Deque<Integer> deque = new LinkedList<>();

     void offer(Integer val){                   //此处参数类型 Integer 
        while(!deque.isEmpty()&& val>deque.getLast()){
            deque.removeLast();
        }
        deque.offer(val);
     }

    void poll(Integer val){              //此处参数类型 Integer           
        if(!deque.isEmpty()&&val==deque.peek()){
               deque.poll();
        }
    }

        Integer peek() {                 //此处返回值类型 Integer 
            return deque.peek();
        }

    }

    public int[] maxSlidingWindow(int[] nums, int k) {
        
        
        if (nums.length == 1)
            return nums;
            MyQue myQue = new MyQue();
        int len = nums.length - (k - 1);
        int[] res = new int[len];
        for (int i = 0; i < k; i++) {
            myQue.offer(nums[i]);

        }
        int num = 0;
        res[num++] = myQue.peek();
        for (int i = k; i < nums.length; i++) {
            myQue.poll(nums[i - k]);
            myQue.offer(nums[i]);
            res[num++] = myQue.peek();
        }
        return res;

    }
}

正确的答案

class Solution {

    class MyQue {
        Deque<Integer> deque = new LinkedList<>();

     void offer(int val){                //此处参数为int
        while(!deque.isEmpty()&& val>deque.getLast()){
            deque.removeLast();
        }
        deque.offer(val);
     }

    void poll(int val){              //此处参数为 int      
        if(!deque.isEmpty()&&val==deque.peek()){
               deque.poll();
        }
    }

        int peek() {                   //此处返回值类型为 int    
            return deque.peek();
        }

    }

    public int[] maxSlidingWindow(int[] nums, int k) {
        
        
        if (nums.length == 1)
            return nums;
            MyQue myQue = new MyQue();
        int len = nums.length - (k - 1);
        int[] res = new int[len];
        for (int i = 0; i < k; i++) {
            myQue.offer(nums[i]);

        }
        int num = 0;
        res[num++] = myQue.peek();
        for (int i = k; i < nums.length; i++) {
            myQue.poll(nums[i - k]);
            myQue.offer(nums[i]);
            res[num++] = myQue.peek();
        }
        return res;

    }
}