LeetCode 2103.环和杆

原题链接：力扣（LeetCode）官网 - 全球极客挚爱的技术成长平台

C++代码

常规

class Solution {
public:
    int countPoints(string rings) {
        int count = 0;
        set<string>se[10];
        for(int i=1,j=0;i<rings.length();i+=2,j+=2){
            se[rings[i]-'0'].insert(to_string(rings[j]));
        }

        for(int i=0;i<10;i++){
            if(se[i].size()==3) count++;  
        }
        
        return count;
    }
};

Python代码

位运算

class Solution:
    def countPoints(self, rings: str) -> int:
        n,count = len(rings),0
        binary_map = [0]*17  # R - B = 17
        for i in range(0,n,2):
            binary_map[ord(rings[i]) - ord('B')] |= 1 << (int(rings[i+1]) - int('0'))  
        for i in range(10):
            tmp = 0
            for ch in ['R','G','B']:
                tmp += (binary_map[ord(ch)-ord('B')] >> i) & 1  #第i根杆 上是否有ch颜色的圈
            if tmp == 3:
                count += 1
        return count