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Sep 22, 2023AustinLeath
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LeetCode Flood Fill

Oct 15, 2022CodeCatch

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class Solution(object):
def floodFill(self, image, sr, sc, newColor):
R, C = len(image), len(image[0])
color = image[sr][sc]
if color == newColor: return image
def dfs(r, c):
if image[r][c] == color:
image[r][c] = newColor
if r >= 1: dfs(r-1, c)
if r+1 < R: dfs(r+1, c)
if c >= 1: dfs(r, c-1)
if c+1 < C: dfs(r, c+1)
dfs(sr, sc)
return image

integer to roman numeral

Nov 19, 2022CodeCatch

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def to_roman_numeral(num):
lookup = [
(1000, 'M'),
(900, 'CM'),
(500, 'D'),
(400, 'CD'),
(100, 'C'),
(90, 'XC'),
(50, 'L'),
(40, 'XL'),
(10, 'X'),
(9, 'IX'),
(5, 'V'),
(4, 'IV'),
(1, 'I'),
]
res = ''
for (n, roman) in lookup:
(d, num) = divmod(num, n)
res += roman * d
return res
to_roman_numeral(3) # 'III'
to_roman_numeral(11) # 'XI'
to_roman_numeral(1998) # 'MCMXCVIII'

Sieve of Eratosthenes

Nov 19, 2022CodeCatch

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# Given a number n, print all primes smaller than or equal to n. It is also given that n is a small number.
# For example, if n is 10, the output should be “2, 3, 5, 7”. If n is 20, the output should be “2, 3, 5, 7, 11, 13, 17, 19”.
# Python program to print all primes smaller than or equal to
# n using Sieve of Eratosthenes
def SieveOfEratosthenes(n):
# Create a boolean array "prime[0..n]" and initialize
# all entries it as true. A value in prime[i] will
# finally be false if i is Not a prime, else true.
prime = [True for i in range(n + 1)]
p = 2
while (p * p <= n):
# If prime[p] is not changed, then it is a prime
if (prime[p] == True):
# Update all multiples of p
for i in range(p * 2, n + 1, p):
prime[i] = False
p += 1
prime[0]= False
prime[1]= False
# Print all prime numbers
for p in range(n + 1):
if prime[p]:
print (p)
# driver program
if __name__=='__main__':
n = 30
print("Following are the prime numbers smaller")
print("than or equal to ", n)
print("than or equal to ", n)
SieveOfEratosthenes(n)

when predicate lambda

Nov 19, 2022CodeCatch

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def when(predicate, when_true):
return lambda x: when_true(x) if predicate(x) else x
double_even_numbers = when(lambda x: x % 2 == 0, lambda x : x * 2)
print(double_even_numbers(2)) # 4
print(double_even_numbers(1)) # 1

Append to a file

Jun 1, 2023CodeCatch

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filename = "data.txt"
data = "Hello, World!"
with open(filename, "a") as file:
file.write(data)

Delete all even numbers

Nov 19, 2022CodeCatch

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# Deleting all even numbers from a list
a = [1,2,3,4,5]
del a[1::2]
print(a)