华为校招主管面

原题链接：
https://leetcode.cn/problems/cinema-seat-allocation/description/

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
class Solution {
    private int left = 0b11110000;
    private int middle = 0b11000011;
    private int right = 0b00001111;

    public int maxNumberOfFamilies(int n, int[][] reservedSeats) {
        HashMap<Integer,Integer>hash = new HashMap<>();

        for(int i = 0; i < reservedSeats.length ; i++){
            int row = reservedSeats[i][0];
            int col = reservedSeats[i][1];  
            // 最左和最右两个位置为 无效位置
            if(col <= 1 || col >= 10){
                continue;
            }
            int mask = hash.getOrDefault(row,0);
            // 左右两个位置 无效直接忽略
            hash.put(row, mask | 1 << (col - 2));
        }
        
        // 直接反向做可以加速 否则会超时 
        int ans = (n - hash.size()) * 2;

        // 只对 有预约的行进行操作
        for(var es : hash.entrySet()){
            int row = es.getKey();
            int seats = es.getValue();
            
            if((seats | left) == left || (seats | middle) == middle || (seats | right) == right){
                ans++;
            }
        }

        return ans;
    }
}