Project Euler & HackerRank Problem 13 Solution

Large sum
by {BetaProjects} | MAY 17, 2009 | Project Euler & HackerRank

Project Euler Problem 13 Statement

Work out the first ten digits of the sum of the following one-hundred 50-digit numbers.

```37107287533902102798797998220837590246510135740250
46376937677490009712648124896970078050417018260538
… {data continues}```

Solution

Summing a set of 50–digit numbers uses Python’s intrinsic arbitrary–precision integers and arithmetic.

The numbers to add are saved to a file named pe13.txt. This keeps the data and the program separate and the process easy to comprehend.

The file is read as strings and converted to a list of integers using the `map` function with `open` as the iterator and `int` as the application function:

`total = sum(map(int, open('pe13.txt')))`.

After the end of the file is reached the list is fed to the `sum` function which adds the integers together:

`total = sum(map(int, open('pe13.txt')))`.

Finally, the integer sum, `total`, is converted to a string and truncated to the top 10 digits for a solution.

`str(total)[:10]`

HackerRank version

HackerRank Project Euler 13 increases the quantity of 50–digit numbers from 100 to 1,000. No changes are required.