Count zeros in a row wise and column wise sorted matrix

Count zeros in sorted matrix

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Count zeros in a row wise and column wise sorted matrix Lets understand the problem statement graphically and it will be more clear,

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Search in a row wise and column wise sorted matrix

Find number in sorted matrix

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Given an n x n matrix, where every row and column is sorted in increasing order.  Given a number k, how to decide whether this k is in the matrix. OR Search number in a row wise and column wise sorted matrix.

Lets understand the problem statement graphically and it will be more clear,

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Find middle element of a linked list

Find middle element of a linked list in Java

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Given a singly linked list find middle of the linked list.

Find Nth node from last in a linked list

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Convert Sorted Linked List to balanced BST

Convert Sorted Linked list to balanced Binary Search Tree

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Convert sorted list to binary search tree

Lets simplify the question statement, Given a singly Linked List where elements are sorted in  ascending order convert it to a height balanced BST.

A Binary Search Tree is called balanced if the height of left subtree and height of right subtree of Root differ by at most 1.

Lets understand the problem statement graphically and it will be more clear,

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Sorted Array to Balanced Binary Search Tree (BST)

Convert Sorted Array to Balanced Binary Search Tree

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Given a sorted array, create a Balanced Binary Search Tree using array elements. A Binary Search Tree is called Balanced if, the height of left subtree and height of right subtree of Root differ by at most 1.

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Union and Intersection of Two Sorted Arrays

Union and Intersection of Two Sorted arrays

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Given two sorted arrays of any length, Find Union and Intersection of given arrays.

Lets understand the problem statement graphically and it will be more clear,

Union and Intersection of two arrays in Java 

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Merge two sorted arrays in Java

Merge two sorted arrays Java 

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Merge two sorted arrays in java.
Lets simplify problem statement, given two sorted arrays, you need to merge it in one array such that merged array should also be sorted. 
 
Lets understand the problem statement graphically and it will be more clear,

Merge two sorted arrays in Java 

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Clone linked list with next and random pointer

Clone linked list with next and random pointer

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You are given a Doubly Link List with one pointer of each node pointing to the next node just like in a singly link list. The second pointer however can point to any node in the list and not just the previous node.
 
Lets understand the problem statement graphically and it will be more clear,

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Clone Linked list in Java

Copy linked list in Java

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Given a Linked list, Create a deep copy of Linked list.

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Serialize and Deserialize a Binary Tree

Serialize and Deserialize a Binary Tree

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Design an algorithm to serialize and deserialize given Binary Tree.  Serialization is to store tree in a File/String, so that it can be later restored. 
Deserialization is reading tree back from file.

Lets understand the problem statement graphically and it will be more clear,

We need to Serialize given Binary Tree into String(So that we can write it to File or transfer it). 

Also, we need to read the Serialized String and Deserialize it back to original Binary Tree.

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Trapping Rain Water between Towers

How Much Water Can A Bar Graph Hold 

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Given an bar graph, encoded as an array of non-negative integers, calculate the units of water that this bar graph can hold.

Let us put in technical terms,
Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining. Lets understand the problem statement graphically and it will be more clear,

Case 1:
Input     = [2, 0, 2]
Output  = 2


Case 2:
Input     = [3, 0, 0, 2, 0, 4]
Output  = 10

Case 3:
Input     = [0, 1, 0, 2, 1, 0, 1, 3, 2, 1, 2, 1]
Output  =  6

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