tdd for coding practices - by zhifu ge
TRANSCRIPT
TDD for Coding PracticesA demo by Zhifu Ge
Why Practice?
Because all professionals do
working is not practicing
–Robert C. Marin
“You should plan on working 60 hours per week. The first 40 are for your employer. The
remaining 20 are for yourself. ”
Why TDD
It gives me the peace of mind
How to TDD
• write enough test for it to fail • write enough code for the test to pass • repeat as necessary
Why Minitest
it’s simple and does everything the other guys do
How to Minitest
require “minitest/autorun”
def MyTest < Minitest::Test def test_meaning_of
life = Life.new assert_equal 42, meaning_of(life); endend
The problem• The definition of equilibrium index
• Sum of 0 elements are 0
• Worst-case time complexity is O(N)
Prefix Sum
Index(i) 0 1 2 3 4 5 6 7 8
a -1 3 -4 5 1 -6 2 1
prefix_sum 0 -1 2 -2 3 4 -2 0 1
the sum of a[p] to a[q] is prefix_sum[q + 1] - prefix_sum[p]
The Demo
