【每日一题Day366】LC2103环和杆 | 状态压缩

class Solution {
    public int countPoints(String rings) {
        int[] mask = new int[10];
        Map<Character, Integer> map = new HashMap<>();
        map.put('R', 1);
        map.put('G', 2);
        map.put('B', 4);
        for (int i = 0; i < rings.length(); i += 2){
            int val = map.get(rings.charAt(i));
            int index = rings.charAt(i + 1) - '0';
            mask[index] |= val;
        }
        int res = 0;
        for (int i = 0; i < 10; i++){
            if (mask[i] == 7){
                res++;
            }
        }
        return res;
    }
}