Valid Subsequence Verification ā Problem Statement & Solution Guide
Problem Description
Given two arrays, determine if one array representing a sequence of ingredients is a valid subsequence of another array representing a recipe.
Examples
Input
[4, 3, 2], [1, 2, 3, 4]
Output
true
Explanation: Step-by-step: with input [4, 3, 2], we push elements from the recipe array [1, 2, 3, 4] into the stack. When we encounter 4 in the sequence array, we pop elements from the stack until we find a match. We repeat this process until we find all elements from the sequence array in the correct order, giving output true.
Input
[1, 3], [1, 2, 3, 4]
Output
true
Explanation: Step-by-step: with input [1, 3], we push elements from the recipe array [1, 2, 3, 4] into the stack. When we encounter 1 in the sequence array, we pop elements from the stack until we find a match. We repeat this process until we find all elements from the sequence array in the correct order, giving output true.
Constraints
- 1 <= sequence length <= 100
- 1 <= recipe length <= 500
Optimal Approach & Strategy
The optimal approach involves using a stack data structure to keep track of the sequence elements that have been found in the recipe array so far, resulting in a time complexity of O(n). This approach is efficient and should be used to solve the problem.
Brute Force Approach
The brute-force approach involves iterating through the recipe array for each ingredient in the sequence, resulting in a time complexity of O(nĀ²). This approach is inefficient and should be avoided. It can be implemented using nested loops to check for the presence of each ingredient in the sequence.
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