The problem
You’ve got an array of integers and have a frog on the first place
[Frog, int, int, int, ..., int]
The integer itself could inform you the size and the course of the bounce
For example:
2 = bounce two indices to the correct
-3 = bounce three indices to the left
0 = keep on the identical place
Your goal is to seek out what number of jumps are wanted to leap out of the array.
Return -1 if Frog can’t bounce out of the array
Instance:
array = [1, 2, 1, 5];
jumps = 3 (1 -> 2 -> 5 -> <bounce out>)
The answer in Python code
Possibility 1:
def resolution(a):
if not a: return -1
posSet, i = set(), 0
whereas i not in posSet:
posSet.add(i)
i += a[i]
if not (0 <= i < len(a)):
return len(posSet)
return -1
Possibility 2:
def resolution(a):
steps = 0
index = 0
size = len(a)
indexes = set()
whereas 0 <= index < size:
if index in indexes:
return -1
indexes.add(index)
index += a[index]
steps += 1
return steps
Possibility 3:
def resolution(a):
c = i = 0
whereas i >= 0 and that i < len(a) and c<20 : i += a[i] ; c += 1
return [c,-1][c==20]
Check circumstances to validate our resolution
import take a look at
from resolution import resolution
@take a look at.describe("Pattern exams")
def _():
@take a look at.it("Assessments")
def __():
take a look at.assert_equals(resolution([1, 2, 2, -1]), 4)
take a look at.assert_equals(resolution([1, 2, 1, 5]), 3)
take a look at.assert_equals(resolution([1, -1]), -1)
