LeetCode/BullsAndCows.java at master · EricZhengH/LeetCode · GitHub

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/**
 * Created by Baiye on 2016/12/13.
 */

/**
 * LeetCode.299.Bulls and Cows
 */
public class BullsAndCows {

    public String getHint(String secret, String guess) {

        if (secret == null || guess == null || secret.length() != guess.length()) {
            return "";
        }

        int countA = 0;
        int countB = 0;
        int[] count = new int[10];

        for (int i = 0; i < secret.length(); i++) {
            if (secret.charAt(i) == guess.charAt(i)) {
                countA++;
            } else {
                count[secret.charAt(i) - '0']++;
                if (count[secret.charAt(i) - '0'] <= 0) {
                    countB++;
                }
                count[guess.charAt(i)- '0']--;
                if (count[guess.charAt(i)- '0'] >= 0) {
                    countB++;
                }
            }
        }

        return String.valueOf(countA) + "A" + String.valueOf(countB) + "B";
    }
}