diff options
Diffstat (limited to 'users/wpcarro/scratch/facebook/recursion-and-dynamic-programming/magic-index.py')
-rw-r--r-- | users/wpcarro/scratch/facebook/recursion-and-dynamic-programming/magic-index.py | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/users/wpcarro/scratch/facebook/recursion-and-dynamic-programming/magic-index.py b/users/wpcarro/scratch/facebook/recursion-and-dynamic-programming/magic-index.py new file mode 100644 index 000000000000..03b2de015dfe --- /dev/null +++ b/users/wpcarro/scratch/facebook/recursion-and-dynamic-programming/magic-index.py @@ -0,0 +1,33 @@ +from math import floor + +def find_magic_index_brute(xs): + for i in range(len(xs)): + if xs[i] == i: + return i + return -1 + +def mid(lo, hi): + return lo + floor((hi - lo) / 2) + +def find_magic_index(xs): + lo, hi = 0, len(xs) - 1 + return do_find_magic_index(xs, 0, len(xs) - 1) + +def do_find_magic_index(xs, lo, hi): + pass + +xss = [ + [], + [-1,0,2,4,5,6], + [1,1,1,1,1,5], + [-2,-2,-2,-2,4], + [1,2,3,4,5], +] + +for xs in xss: + print(xs) + a = find_magic_index_brute(xs) + b = find_magic_index(xs) + print(a, b) + assert a == b + print("Success!") |