marinskiy/hackerrankpractice

170+ solutions to Hackerrank.com practice problems using Python 3, С++ and Oracle SQL

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Fibonacci

# Iterative solution
def fibonacci(n):
    # special case
    if n == 1:
        return [0]
    # initialize the array
    arr = [0, 1]
    # and populate it, remember to skip the 2 values that are already
present
    for i in range(2, n):
        arr.append(arr[-1]+arr[-2])
    return arr


# Recursive solution
def fibonacci(n):
    # handle special cases
    print(n)
    if n < 2:
        return [0]
    if n < 3:
        return [0, 1]
    # normal case as n decreases from original value to 2
    arr = fibonacci(n-1)
    arr.append(arr[n-2] + arr[n-3])
    return arr

Find the sequence Sum

def getSequenceSum(i, j, k, x):
    cnt_inc = (j - i) // x + 1
    cnt_dec = (j - k) // x + 1
    inc_sum = (cnt_inc * (i + j)) // 2
    dec_sum = (cnt_dec * (j + k)) // 2
    tot_sum = inc_sum + dec_sum - j
    return tot_sum

Maximizing Profit from Stocks

def maximumProfit(prices):
    m = prices.pop()
    maxsum = 0
    arrsum = 0
    for p in reversed(prices):
        m = max(m, p)
        maxsum+=m
        arrsum+=p
    return maxsum-arrsum

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