题目

word-pattern

算法

* 哈希

* 优化

代码

* 哈希

class Solution {
public:
    string getHint(string secret, string guess) {
        int m[256] = {0}, bulls = 0, cows = 0;
        for (int i = 0; i < secret.size(); ++i) {
            if (secret[i] == guess[i]) ++bulls;
            else ++m[secret[i]];
        }
        for (int i = 0; i < secret.size(); ++i) {
            if (secret[i] != guess[i] && m[guess[i]]) {
                ++cows;
                --m[guess[i]];
            }
        }
        return to_string(bulls) + "A" + to_string(cows) + "B";
    }
};

* 优化

class Solution {
public:
    string getHint(string secret, string guess) {
        int m[256] = {0}, bulls = 0, cows = 0;
        for (int i = 0; i < secret.size(); ++i) {
            if (secret[i] == guess[i]) ++bulls;
            else {
                if (m[secret[i]]++ < 0) ++cows;
                if (m[guess[i]]-- > 0) ++ cows;
            }
        }
        return to_string(bulls) + "A" + to_string(cows) + "B";
    }
};

* 再优化

class Solution {
public:
    string getHint(string secret, string guess) {
        int m[256] = {0}, a = 0, b = 0, i = 0;
        for (char s : secret) {
            char g = guess[i++];
            a += s == g;
            b += (m[s]++ < 0) + (m[g]-- > 0);
        }
        return to_string(a) + "A" + to_string(b - a) + "B";
    }
};