100 days badge of 2024

[LeetCode] 2825. Make String a Subsequence Using Cyclic Increments

Problem : https://leetcode.com/problems/make-string-a-subsequence-using-cyclic-increments/

There are 2 important rules:

We only need to increase cyclically the character of str1 to match with a character of str2.

We only need to check if str2 is one of subsequences of str1. So we can use 2 pointers to compare the charaters of str1 and str2. When str1[i] == str2[j], we can move the 2 pointers forward. Otherwise, we just move forward the pointer i.

class Solution {

    public boolean canMakeSubsequence(String str1, String str2) {
        int M = str1.length(), N = str2.length();             
        int i = 0, j = 0;
        
        while (i < M && j < N) {
            int a = str1.charAt(i) - 'a', b = str2.charAt(j) - 'a';
            
            if (a == b || (a + 1) % 26 == b) {
                i += 1;
                j += 1;
            } else {
                i += 1;
            }
        }
        
        // Check if all characters of str2 have been matched
        return j == N;
    }
}