This is a premium problem. We're working on making it available for free soon.
Explore Free ProblemsSolutions for this premium problem will be available for free soon.
Browse Free ProblemsWatch expert explanations and walkthroughs
Practice problems asked by these companies to ace your technical interviews.
Explore More ProblemsJot down your thoughts, approach, and key learnings
While it is categorized as an easy problem, similar matrix validation and string indexing problems are common in technical interviews, including FAANG-style assessments. It helps test attention to detail, boundary handling, and basic matrix reasoning.
The optimal approach is to compare characters symmetrically using indices (i, j) and (j, i). By iterating through each row and verifying the corresponding column character while checking boundaries, you can determine if the words form a valid square in linear time relative to the total characters.
Words can have different lengths, so accessing characters blindly may cause out-of-bounds errors. Proper checks ensure that when comparing (i, j) and (j, i), both positions exist in the input before validating their characters.
An array or list of strings is sufficient for this problem. You can treat the list as a character matrix and directly access characters using indices, which allows efficient row and column comparison without extra memory.