leetcode383 Ransom letter

Topic link ：leetcode

Thought analysis

The letters in the title are all lowercase characters , So we consider using arrays to map using hash algorithm , We will magazine Array mapping , Add it at the specified position 1.
And then we went to randomNote Traversal , Subtract one from the mapped position , Finally, let's see if there is less than 0 It's a good number , If there is less than 0 It proves that there are other elements in the array , That's not right , Go straight back to false, If there is no less than 0 Yes, then go back true.

Code

class Solution {
    
    public boolean canConstruct(String ransomNote, String magazine) {
    
        int[] nums = new int[26];

        for (int i = 0; i < magazine.length(); i++) {
    
            nums[magazine.charAt(i) - 'a'] += 1;
        }

        for (int i = 0; i < ransomNote.length(); i++) {
    
            nums[ransomNote.charAt(i) - 'a'] -= 1;
        }

        for (int num : nums) {
    
            if (num < 0){
    
                return false;
            }
        }
        return true;

    }
}