Make String a Subsequence Using Cyclic Increments

Leetcode Problem:

• Make String a Subsequence Using Cyclic Increments

Summary

• Given two strings, check if str2 can be made a subsequence of str1 by performing the operation at most once.

Approach

• The approach used is to iterate over each character in str1 and check if it is equal to the current character in str2 or the next character in str1 (cyclically)
• If it is, increment the pointer for str2.

Complexity

• O(n), where n is the length of str1

Explanation

• The solution iterates over each character in str1 and checks if it is equal to the current character in str2 or the next character in str1 (cyclically)
• If it is, increment the pointer for str2
• If the pointer for str2 reaches the end of str2, return true
• Otherwise, return false.

Solution Code:

class Solution {
public:

    bool canMakeSubsequence(string str1, string str2) {
        int j = 0;
        for(int i = 0 ; i < str1.size(); i++){
            char next = str1[i] == 'z' ? 'a' : str1[i] + 1;
            if(j < str2.size() && (str1[i] == str2[j] || str2[j] == next)){
                j++;
            }
        }
        if (j >= str2.size()) return true;
        return false;
    }
};