Coding Interview

1. Constraints:

Input:

• Data Structure of Input and Limits/Constraints on Input
  • Empty, Null
  • Numeric – Integer/Long, double/float, Negative/Positive, Zero, Duplicates, SORTED ?   MIN and MAX Value allowed
  • Sting – ASCII, UNICODE, English alphabets(a-z), case(lowercase/uppercase), SORTED    (lexicographically) ? 
  • Linked List – Single/Double, Node values, size available, head and/or tail present, Cycle ?
  • Tree – Binary/N-ary, BST, Parent, Node(Key), Duplicates ?
  • Graph – Directed/Undirected, Connected, Cycle, Weighted ? Input type adj list, adj matrix, edges etc. ?
• Streaming or Fixed size input ?
• Limits/Constraints on Input 
• Can Input be Modified ?

Output:

• Data Structure of Output and Limits/Constraints on Input
  • Output sorted ? number sort ? string sort ? 
  • how to handle empty or null or base cases ? 
• New Object Creation ? In Place ?

High Level:

• How many times will it (method or class) be called ?
• How will it (method or class) be accessed ?
• Single Core enough to process ?
• Enough Memory Available ?
• Distributed ?
• Expected Time and Space Complexity ? (Debatable to ask or not .. could ask diplomatically)

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2. Test Cases:

• Come up with new Test cases
  • large size
  • small size
  • null or empty
• Think/Discuss/Solve the solution for these Test cases

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3. Algorithm :

• Discuss
  • Start with brute force approach if possible
  • Data structure
    • Tradeoff of using 1 data structure over over
    • Tradeoff of various ways of data structure traversals (like bfs, dfs …)
  • Complexities
    • Tradeoff of complexities time n space of one approach over another .. high level only
    • DONT FORGET to mention complexity variable name’s meanings like n is for input size .. etc.
• Solve
  • Solve using all the test cases … run the algorithm so to speak
• Write
  • High level algorithm / pseudocode to refer later when coding
  • Various cases if present eg: if else, multiple if’s

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4. Coding:

• Modularize code .. methods .. top down approach
• explanative variable names … feel free to use additional variables for readability … duplicate operations like +1 -1 can be saved in a new variable
• Think and write space and time complexity after coding 

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Resources:

the-common-constraints-handoutDownload