Jason-Stan-Lee / Algrithem

Solutions to some algrithem questions

Algrithem

Solutions to some algrithem questions

1. Number if tasks running:

   Given n tasks that start and end at (unix) time:(n < 1000)

      [start 1, end 1), [start 2, end 2), ... , [start n, end n)
      of which all starting times are inclusive and all ending times are exclusive
   

   Write code to efficiently return the number of tasks that are running at m given times:(m > 100000) query 1, query 2, ... , query m

   Function Definition

   void number_of_tasks_running( OUT int number_of_tasks_running[], IN int start[], IN int end[], IN int n, IN int query[], IN int m) {

   }

   Example

   input:

     n = 3;
     m = 4;
     start = [0, 5, 2];
     end = [4, 7, 8];
     query = [1, 9, 4, 3];
   

   output:

     [1, 0, 1, 2]
   

2. Find missed number:

   Given an array which have n-1 items,

   the range of this items is [1, n],

   the array missed one of them,

   Write code to find the missed number.

   Function Definition

   int find_missed_number( int array[], int n)

   {

   }

   input:

    int array[] = {1, 2, 4};
    n = 4;
   

   output:

    3;
   

3. Number of digit one:

   From Leet Code 233:

   Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.

   For example:

   Given n = 13,

   Return 6, because digit 1 occurred in the following numbers: 1, 10, 11, 12, 13.