HackerRank Algebra – Wet Shark and 42

Challenge: Wet Shark and 42

Subdomeniu: Algebra (algebra)

Scor cont: 20.0 / 20

Submission status: Accepted

Submission score: 1.0

Submission ID: 464723749

Limbaj: python3

Link challenge: https://www.hackerrank.com/challenges/wet-shark-and-42/problem

Cerinta

As punishment for attacking Sunland, Wet Shark is now forced to walk on a line of numbered squares, starting from $1$ and going to infinity. Wet Shark initially has a strength of $S$. To make the experience harder for Wet Shark, each square that has a label divisible by $4$ and/or $2$ but not divisible by $42$ contains a black glob of jelly, stepping on which his strength decreases by $1$. 

Wet Shark does not know that this line of squares is infinitely long, and he is determined to continue walking until his strength reaches $0$. Wet Shark walks from square to square, so he starts at square $1$, goes to square $2$, then $3$, then $4$, etc. 

Wet Shark’s punisher needs your help, and wants to compute where Wet Shark will stop in order to meet him there and punish him. Given Wet Shark’s initial strength $S$, find the square on which Wet Shark’s strength will reach $0$. Wet Shark can go far if defenses are not strong enough, so please output the answer modulo $10^9+7$. Wet Shark is curious, so he wants to know that given $S$ strength initially, how far he will go for different values $S$. Help him figure out how long he can go without doom for each $S$.

Input Format

The first line of the input contains an integer $T$, the number of queries. The following lines describe the queries.

Each query consists of a line containing a single integer, which is the value of $S$.

Output Format

Print $T$ lines, each line containing the answer for each query, i.e. the last square Wet Shark will reach before he runs out of strength, starting with a strength of $S$, modulo $10^9+7$.

**Constraints**  

$1 \le T \le 100$  
$1 \le S \le 10^{18}$

Cod sursa

#!/bin/python3

import math
import os
import random
import re
import sys

def solve(S):  # S = initial strength
    mod_n = 10**9 + 7
    if S%20 != 0:
        return ((S//20)*42 + (S%20)*2) % mod_n  
    else:
        return ((S//20)*42 - 2) % mod_n
if __name__ == '__main__':
    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    t = int(input().strip())

    for t_itr in range(t):
        s = int(input().strip())

        result = solve(s)

        fptr.write(str(result) + '\n')

    fptr.close()