Amazon Interview experience | Set 328 (For SDE-1)

Started with online test at Hackerearth. It had 2 questions. 

1. Find subarray with max sum. Array have both -ve and +ve integers.
2. Consider a matrix with rows and columns, where each cell contains either a 0 or a 1 and any cell containing a 1 is called a filled cell. Two cells are said to be connected if they are adjacent to each other horizontally, vertically, or diagonally; 
   If one or more filled cells are also connected, they form a region. 
   Output the length of the largest region. 

   Ex: in the following example, there are 2 regions one with length 1 and the other as 6. 
   0 0 1 1 0 
   1 0 1 1 0 
   0 1 0 0 0 
   0 0 0 0 1 
   Solution: Unit Area of largest region of 1’s

1st Round (telephonic)

1. Given a string and integer k, in-place rearrange the string such that last n-k characters comes before the first k characters. 
   Ex: abcdef and k=3, so result is: defabc
2. Given a binary tree, sum all the root to leaf nodes and return the sum.

Ex:  
          1
        /   \
      2      3
    /   \       \
   4     6       7

here ans: 124 + 126 + 137 = 387

2nd Round

1. Given a large file having strings(for understanding, given an array of strings). Find the string which repeats the most. Ignore the case.
2. Given the link-list and integer value ‘k’, reverse every k nodes of the list.
   Ex. k = 3, list: 1-2-3-4-5-6-7-8 
   ans: 3-2-1-6-5-4-8-7

3rd Round

1. Questions on my projects.
2. Given a binary tree with each node having parent pointers. Find the LCA of two nodes.

4th Round

1. Given a 2-D grid, number of steps to take, say k and initial position of a Robot. print the paths possible from initial position after k steps. Robot can move in top, right, left, bottom. In one path, robot can’t move to the location it has previously visited.
2. Check if a binary tree is balanced. Balance criteria was difference of height between left and right subtree should be <= 1.
3. Given a binary tree, a node of that tree, and integer k. Print all the nodes which are at distance k from that node. NOTE: there is no parent pointer in the node.

5th Round

1. Behavioral Questions. Read front pages(before technical stuff) of Cracking the coding interview book. Prepare them well.
2. Given a string, count all the palindromes in that string. Only consider substring palindromes

Thanks to geeksforgeeks for helping me prepare for interviews. 

All Practice Problems for Amazon !