【LeetCode】383. Ransom letter

Subject: 383. Ransom Letter

Since this question only contains lowercase letters, and the letters in the magazine cannot be reused.

Therefore, first use an integer array with a length of 26 to record the number of occurrences of letters in the magazine.

Then use this integer array to traverse and compare with ransomeNote. When -1 appears in the array, it means false, otherwise true.

code:

class Solution {
    public boolean canConstruct(String ransomNote, String magazine) {
        int[] tmp = new int[26];
        
        //遍历magazine中的字符
        for(int i=0;i<magazine.length();i++){
            char ch = magazine.charAt(i);
            tmp[ch-'a']++;
        }

        //遍历ransomNote中的字符
        for(int i=0;i<ransomNote.length();i++){
            char ch = ransomNote.charAt(i);
            tmp[ch-'a']--;
            if(tmp[ch-'a']<0){
                return false;
            }
        }

        return true;
    }
}

operation result: