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2825. Make String a Subsequence Using Cyclic Increments

MediumOpen on LeetCodeProblem statement

Problem Statement

2825. Make String a Subsequence Using Cyclic Increments

Medium


You are given two 0-indexed strings str1 and str2.

In an operation, you select a set of indices in str1, and for each index i in the set, increment str1[i] to the next character cyclically. That is 'a' becomes 'b', 'b' becomes 'c', and so on, and 'z' becomes 'a'.

Return true if it is possible to make str2 a subsequence of str1 by performing the operation at most once, and false otherwise.

Note: A subsequence of a string is a new string that is formed from the original string by deleting some (possibly none) of the characters without disturbing the relative positions of the remaining characters.

 

Example 1:

Input: str1 = "abc", str2 = "ad"
Output: true
Explanation: Select index 2 in str1.
Increment str1[2] to become 'd'. 
Hence, str1 becomes "abd" and str2 is now a subsequence. Therefore, true is returned.

Example 2:

Input: str1 = "zc", str2 = "ad"
Output: true
Explanation: Select indices 0 and 1 in str1. 
Increment str1[0] to become 'a'. 
Increment str1[1] to become 'd'. 
Hence, str1 becomes "ad" and str2 is now a subsequence. Therefore, true is returned.

Example 3:

Input: str1 = "ab", str2 = "d"
Output: false
Explanation: In this example, it can be shown that it is impossible to make str2 a subsequence of str1 using the operation at most once. 
Therefore, false is returned.

 

Constraints:

Java

Source file
class Solution {
    public boolean canMakeSubsequence(String str1, String str2) {
        int p1 = 0, p2 = 0;
        for(; p1<str1.length() && p2<str2.length(); p1++){
            char c1 = str1.charAt(p1), c2 = str2.charAt(p2);
            if(c1 == c2 || c1 + 1 == c2 || c1-25==c2)
                p2++;
        }
        return p2 == str2.length();
    }
}