2825. Make String a Subsequence Using Cyclic Increments
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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:
1 <= str1.length <= 1051 <= str2.length <= 105str1andstr2consist of only lowercase English letters.
Hints
Hint 1
Consider the indices we will increment separately.
Hint 2
We can maintain two pointers: pointer
i for str1 and pointer j for str2, while ensuring they remain within the bounds of the strings.Hint 3
If both
str1[i] and str2[j] match, or if incrementing str1[i] matches str2[j], we increase both pointers; otherwise, we increment only pointer i.Hint 4
It is possible to make
str2 a subsequence of str1 if j is at the end of str2, after we can no longer find a match.