Is Delete Operation for Two Strings easy or hard?

Delete Operation for Two Strings is rated Medium difficulty. The challenge lies in recognizing that the minimum deletions problem reduces to the Longest Common Subsequence dynamic programming pattern.

Delete Operation for Two Strings Python/Java solution

Python and Java implementations typically compute the LCS using a 2D DP array of size (m+1) x (n+1). After computing the LCS length, return (m - lcs) + (n - lcs). The same logic works in C++, JavaScript, and other languages.

How to solve Delete Operation for Two Strings in O(n)?

Strict O(n) time is not possible for the general case because every character pair may need comparison. The optimal solution runs in O(m*n) using Longest Common Subsequence dynamic programming. Space can be reduced to O(min(m,n)) by storing only two DP rows.

What is the best approach for Delete Operation for Two Strings?

The optimal approach uses Dynamic Programming with Longest Common Subsequence (LCS). First compute the LCS length of the two strings in O(m*n) time. The minimum deletions required equals (m - lcs) + (n - lcs), which removes all characters not part of the shared subsequence.

Is Delete Operation for Two Strings asked at Google/Amazon/Meta?

Dynamic programming problems based on Longest Common Subsequence frequently appear in interviews at companies like Google, Amazon, and Meta. Variants involving edit distance, deletions, or subsequence transformations are common technical interview questions.

What data structure is used in Delete Operation for Two Strings?

The core data structure is a 2D dynamic programming table. Each cell dp[i][j] stores the LCS length for prefixes of the two strings. The algorithm also relies on basic string traversal and index-based comparisons.

What is the time complexity of Delete Operation for Two Strings?

The optimal Dynamic Programming solution runs in O(m*n) time, where m and n are the lengths of the two strings. This comes from filling an LCS DP table that compares each character pair once. Space complexity is O(m*n) or O(min(m,n)) with optimization.

Description Solution Video 9:02

583. Delete Operation for Two Strings

Medium66.0% acceptance4 companies

Given two strings word1 and word2, return the minimum number of steps required to make word1 and word2 the same.

In one step, you can delete exactly one character in either string.

Example 1:

Input: word1 = "sea", word2 = "eat"
Output: 2
Explanation: You need one step to make "sea" to "ea" and another step to make "eat" to "ea".

Example 2:

Input: word1 = "leetcode", word2 = "etco"
Output: 4

Constraints:

1 <= word1.length, word2.length <= 500
word1 and word2 consist of only lowercase English letters.

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583. Delete Operation for Two Strings

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