Leetcode刷题

Problem 299

Posted by Ruizhi Ma on November 2, 2020

Solution URL

https://leetcode.com/submissions/detail/416210633/

代码

class Solution {
    public String getHint(String secret, String guess) {
        //ans: Solution.
        int bulls = 0;
        int cows = 0;
        //use hashmap to store character and its frequence in secret.
        HashMap<Character, Integer> map = new HashMap<>();
        for(char s: secret.toCharArray()){
            map.put(s, map.getOrDefault(s, 0) + 1);
        }

        //iterate the guess string
        int len = guess.length();
        for(int i = 0; i < len; i++){
            char g = guess.charAt(i);
            //if character exists in secret
            if(map.containsKey(g)){
                //check index matches or not
                //if matches, then it is bull
                if(g == secret.charAt(i)){
                    bulls++;

                    //to check whether it is miscount as a cow
                    if(map.get(g) <= 0){
                        cows--;
                    }
                }else{
                    //update cows
                    if(map.get(g) > 0){
                        cows++;
                    }
                }
                //update the frequence of current char
                map.put(g, map.get(g) - 1);
            }
        }

        return bulls + "A" + cows + "B";
    }
}