KeshariPiyush24

Sorting a Stack using Recursion

Intuition

The core idea behind sorting a stack using recursion is to:

1. Remove elements from the stack one by one.
2. Recursively sort the remaining stack.
3. Insert the removed element at the correct position in the sorted stack.

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Reversing a Stack using Recursion

Intuition

The core idea behind reversing a stack using recursion is to:

1. Remove elements from the stack one by one.
2. Recursively reverse the remaining stack.
3. Insert the removed element at the bottom of the reversed stack.

KeshariPiyush24

Prime Number Testing: Methods, Complexity, and Implementations

1. Basic Concept

A prime number is a natural number greater than 1 that is only divisible by 1 and itself.

2. Efficient Prime Testing Methods

2.1 6k ± 1 Method

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Question: 349. Intersection of Two Arrays

Intution:

Time Complexity: $$O(Nlog(M))$$

Space Complexity: $$O(1)$$

Solution:

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Question: Row with max 1s

Intution: Not exactly binary search but we can utilize the fact that it the row is sorted. We have to use 2 pointers approach.

Time Complexity: $$O(n + m)$$

Space Complexity: $$O(1)$$

Solution:

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Question: Frequency In A Sorted Array

Intution:

Time Complexity: $$O(log(n))$$

Space Complexity: $$O(1)$$

Solution:

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Question: Implement Lower Bound

Intution:

Time Complexity: $$O(log(n))$$

Space Complexity: $$O(1)$$

Solution:

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Question: Implement Upper Bound

Intution:

Time Complexity: $$O(log(n))$$

Space Complexity: $$O(1)$$

Solution:

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Question: 153. Find Minimum in Rotated Sorted Array

Intution:

Time Complexity: $$O(log(n))$$

Space Complexity: $$O(1)$$

Solution:

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Question: 367. Valid Perfect Square

Intution:

Time Complexity: $$O(log(n))$$

Space Complexity: $$O(1)$$

Solution: