Problem:


Score : 300 points

Problem Statement

Takahashi loves the number 7 and multiples of K.

Where is the first occurrence of a multiple of K in the sequence 7,77,777,\ldots? (Also see Output and Sample Input/Output below.)

If the sequence contains no multiples of K, print -1 instead.

Constraints

1 \leq K \leq 10^6

K is an integer.

Input

Input is given from Standard Input in the following format:

K

Output

Print an integer representing the position of the first occurrence of a multiple of K. (For example, if the first occurrence is the fourth element of the sequence, print 4.)

Sample Input 1

101

Sample Output 1

4

None of 7, 77, and 777 is a multiple of 101, but 7777 is.

Sample Input 2

2

Sample Output 2

-1

All elements in the sequence are odd numbers; there are no multiples of 2.

Sample Input 3

999983

Sample Output 3

999982



Sample input:
101


Sample output:
4

Submission status: Accepted

Solution code:
# ---------------------------iye ha aam zindegi---------------------------------------------
import math
import heapq, bisect
import sys
from collections import deque, defaultdict
from fractions import Fraction
import sys
mod = 10 ** 9 + 7
mod1 = 998244353

# ------------------------------warmup----------------------------
import os
import sys
from io import BytesIO, IOBase
BUFSIZE = 8192


class FastIO(IOBase):
    newlines = 0

    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = "x" in file.mode or "r" not in file.mode
        self.write = self.buffer.write if self.writable else None

    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()

    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()

    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)


class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")


sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")


# -------------------game starts now----------------------------------------------------import math
class TreeNode:
    def __init__(self, k, v):
        self.key = k
        self.value = v
        self.left = None
        self.right = None
        self.parent = None
        self.height = 1
        self.num_left = 1
        self.num_total = 1


class AvlTree:

    def __init__(self):
        self._tree = None

    def add(self, k, v):
        if not self._tree:
            self._tree = TreeNode(k, v)
            return
        node = self._add(k, v)
        if node:
            self._rebalance(node)

    def _add(self, k, v):
        node = self._tree
        while node:
            if k < node.key:
                if node.left:
                    node = node.left
                else:
                    node.left = TreeNode(k, v)
                    node.left.parent = node
                    return node.left
            elif node.key < k:
                if node.right:
                    node = node.right
                else:
                    node.right = TreeNode(k, v)
                    node.right.parent = node
                    return node.right
            else:
                node.value = v
                return

    @staticmethod
    def get_height(x):
        return x.height if x else 0

    @staticmethod
    def get_num_total(x):
        return x.num_total if x else 0

    def _rebalance(self, node):

        n = node
        while n:
            lh = self.get_height(n.left)
            rh = self.get_height(n.right)
            n.height = max(lh, rh) + 1
            balance_factor = lh - rh
            n.num_total = 1 + self.get_num_total(n.left) + self.get_num_total(n.right)
            n.num_left = 1 + self.get_num_total(n.left)

            if balance_factor > 1:
                if self.get_height(n.left.left) < self.get_height(n.left.right):
                    self._rotate_left(n.left)
                self._rotate_right(n)
            elif balance_factor < -1:
                if self.get_height(n.right.right) < self.get_height(n.right.left):
                    self._rotate_right(n.right)
                self._rotate_left(n)
            else:
                n = n.parent

    def _remove_one(self, node):
        """
        Side effect!!! Changes node. Node should have exactly one child
        """
        replacement = node.left or node.right
        if node.parent:
            if AvlTree._is_left(node):
                node.parent.left = replacement
            else:
                node.parent.right = replacement
            replacement.parent = node.parent
            node.parent = None
        else:
            self._tree = replacement
            replacement.parent = None
        node.left = None
        node.right = None
        node.parent = None
        self._rebalance(replacement)

    def _remove_leaf(self, node):
        if node.parent:
            if AvlTree._is_left(node):
                node.parent.left = None
            else:
                node.parent.right = None
            self._rebalance(node.parent)
        else:
            self._tree = None
        node.parent = None
        node.left = None
        node.right = None

    def remove(self, k):
        node = self._get_node(k)
        if not node:
            return
        if AvlTree._is_leaf(node):
            self._remove_leaf(node)
            return
        if node.left and node.right:
            nxt = AvlTree._get_next(node)
            node.key = nxt.key
            node.value = nxt.value
            if self._is_leaf(nxt):
                self._remove_leaf(nxt)
            else:
                self._remove_one(nxt)
            self._rebalance(node)
        else:
            self._remove_one(node)

    def get(self, k):
        node = self._get_node(k)
        return node.value if node else -1

    def _get_node(self, k):
        if not self._tree:
            return None
        node = self._tree
        while node:
            if k < node.key:
                node = node.left
            elif node.key < k:
                node = node.right
            else:
                return node
        return None

    def get_at(self, pos):
        x = pos + 1
        node = self._tree
        while node:
            if x < node.num_left:
                node = node.left
            elif node.num_left < x:
                x -= node.num_left
                node = node.right
            else:
                return (node.key, node.value)
        raise IndexError("Out of ranges")

    @staticmethod
    def _is_left(node):
        return node.parent.left and node.parent.left == node

    @staticmethod
    def _is_leaf(node):
        return node.left is None and node.right is None

    def _rotate_right(self, node):
        if not node.parent:
            self._tree = node.left
            node.left.parent = None
        elif AvlTree._is_left(node):
            node.parent.left = node.left
            node.left.parent = node.parent
        else:
            node.parent.right = node.left
            node.left.parent = node.parent
        bk = node.left.right
        node.left.right = node
        node.parent = node.left
        node.left = bk
        if bk:
            bk.parent = node
        node.height = max(self.get_height(node.left), self.get_height(node.right)) + 1
        node.num_total = 1 + self.get_num_total(node.left) + self.get_num_total(node.right)
        node.num_left = 1 + self.get_num_total(node.left)

    def _rotate_left(self, node):
        if not node.parent:
            self._tree = node.right
            node.right.parent = None
        elif AvlTree._is_left(node):
            node.parent.left = node.right
            node.right.parent = node.parent
        else:
            node.parent.right = node.right
            node.right.parent = node.parent
        bk = node.right.left
        node.right.left = node
        node.parent = node.right
        node.right = bk
        if bk:
            bk.parent = node
        node.height = max(self.get_height(node.left), self.get_height(node.right)) + 1
        node.num_total = 1 + self.get_num_total(node.left) + self.get_num_total(node.right)
        node.num_left = 1 + self.get_num_total(node.left)

    @staticmethod
    def _get_next(node):
        if not node.right:
            return node.parent
        n = node.right
        while n.left:
            n = n.left
        return n


# -----------------------------------------------binary seacrh tree---------------------------------------
class SegmentTree1:
    def __init__(self, data, default='z', func=lambda a, b: min(a, b)):
        """initialize the segment tree with data"""
        self._default = default
        self._func = func
        self._len = len(data)
        self._size = _size = 1 << (self._len - 1).bit_length()

        self.data = [default] * (2 * _size)
        self.data[_size:_size + self._len] = data
        for i in reversed(range(_size)):
            self.data[i] = func(self.data[i + i], self.data[i + i + 1])

    def __delitem__(self, idx):
        self[idx] = self._default

    def __getitem__(self, idx):
        return self.data[idx + self._size]

    def __setitem__(self, idx, value):
        idx += self._size
        self.data[idx] = value
        idx >>= 1
        while idx:
            self.data[idx] = self._func(self.data[2 * idx], self.data[2 * idx + 1])
            idx >>= 1

    def __len__(self):
        return self._len

    def query(self, start, stop):
        if start == stop:
            return self.__getitem__(start)
        stop += 1
        start += self._size
        stop += self._size

        res = self._default
        while start < stop:
            if start & 1:
                res = self._func(res, self.data[start])
                start += 1
            if stop & 1:
                stop -= 1
                res = self._func(res, self.data[stop])
            start >>= 1
            stop >>= 1
        return res

    def __repr__(self):
        return "SegmentTree({0})".format(self.data)


# -------------------game starts now----------------------------------------------------import math
class SegmentTree:
    def __init__(self, data, default=0, func=lambda a, b: a + b):
        """initialize the segment tree with data"""
        self._default = default
        self._func = func
        self._len = len(data)
        self._size = _size = 1 << (self._len - 1).bit_length()

        self.data = [default] * (2 * _size)
        self.data[_size:_size + self._len] = data
        for i in reversed(range(_size)):
            self.data[i] = func(self.data[i + i], self.data[i + i + 1])

    def __delitem__(self, idx):
        self[idx] = self._default

    def __getitem__(self, idx):
        return self.data[idx + self._size]

    def __setitem__(self, idx, value):
        idx += self._size
        self.data[idx] = value
        idx >>= 1
        while idx:
            self.data[idx] = self._func(self.data[2 * idx], self.data[2 * idx + 1])
            idx >>= 1

    def __len__(self):
        return self._len

    def query(self, start, stop):
        if start == stop:
            return self.__getitem__(start)
        stop += 1
        start += self._size
        stop += self._size

        res = self._default
        while start < stop:
            if start & 1:
                res = self._func(res, self.data[start])
                start += 1
            if stop & 1:
                stop -= 1
                res = self._func(res, self.data[stop])
            start >>= 1
            stop >>= 1
        return res

    def __repr__(self):
        return "SegmentTree({0})".format(self.data)


# -------------------------------iye ha chutiya zindegi-------------------------------------
class Factorial:
    def __init__(self, MOD):
        self.MOD = MOD
        self.factorials = [1, 1]
        self.invModulos = [0, 1]
        self.invFactorial_ = [1, 1]

    def calc(self, n):
        if n <= -1:
            print("Invalid argument to calculate n!")
            print("n must be non-negative value. But the argument was " + str(n))
            exit()
        if n < len(self.factorials):
            return self.factorials[n]
        nextArr = [0] * (n + 1 - len(self.factorials))
        initialI = len(self.factorials)
        prev = self.factorials[-1]
        m = self.MOD
        for i in range(initialI, n + 1):
            prev = nextArr[i - initialI] = prev * i % m
        self.factorials += nextArr
        return self.factorials[n]

    def inv(self, n):
        if n <= -1:
            print("Invalid argument to calculate n^(-1)")
            print("n must be non-negative value. But the argument was " + str(n))
            exit()
        p = self.MOD
        pi = n % p
        if pi < len(self.invModulos):
            return self.invModulos[pi]
        nextArr = [0] * (n + 1 - len(self.invModulos))
        initialI = len(self.invModulos)
        for i in range(initialI, min(p, n + 1)):
            next = -self.invModulos[p % i] * (p // i) % p
            self.invModulos.append(next)
        return self.invModulos[pi]

    def invFactorial(self, n):
        if n <= -1:
            print("Invalid argument to calculate (n^(-1))!")
            print("n must be non-negative value. But the argument was " + str(n))
            exit()
        if n < len(self.invFactorial_):
            return self.invFactorial_[n]
        self.inv(n)  # To make sure already calculated n^-1
        nextArr = [0] * (n + 1 - len(self.invFactorial_))
        initialI = len(self.invFactorial_)
        prev = self.invFactorial_[-1]
        p = self.MOD
        for i in range(initialI, n + 1):
            prev = nextArr[i - initialI] = (prev * self.invModulos[i % p]) % p
        self.invFactorial_ += nextArr
        return self.invFactorial_[n]


class Combination:
    def __init__(self, MOD):
        self.MOD = MOD
        self.factorial = Factorial(MOD)

    def ncr(self, n, k):
        if k < 0 or n < k:
            return 0
        k = min(k, n - k)
        f = self.factorial
        return f.calc(n) * f.invFactorial(max(n - k, k)) * f.invFactorial(min(k, n - k)) % self.MOD


# --------------------------------------iye ha combinations ka zindegi---------------------------------
def powm(a, n, m):
    if a == 1 or n == 0:
        return 1
    if n % 2 == 0:
        s = powm(a, n // 2, m)
        return s * s % m
    else:
        return a * powm(a, n - 1, m) % m


# --------------------------------------iye ha power ka zindegi---------------------------------
def sort_list(list1, list2):
    zipped_pairs = zip(list2, list1)

    z = [x for _, x in sorted(zipped_pairs)]

    return z


# --------------------------------------------------product----------------------------------------
def product(l):
    por = 1
    for i in range(len(l)):
        por *= l[i]
    return por


# --------------------------------------------------binary----------------------------------------
def binarySearchCount(arr, n, key):
    left = 0
    right = n - 1

    count = 0

    while (left <= right):
        mid = int((right + left) / 2)

        # Check if middle element is
        # less than or equal to key
        if (arr[mid] < key):
            count = mid + 1
            left = mid + 1

        # If key is smaller, ignore right half
        else:
            right = mid - 1

    return count


# --------------------------------------------------binary----------------------------------------
def countdig(n):
    c = 0
    while (n > 0):
        n //= 10
        c += 1
    return c
def binary(x, length):
    y = bin(x)[2:]
    return y if len(y) >= length else "0" * (length - len(y)) + y

def countGreater(arr, n, k):
    l = 0
    r = n - 1

    # Stores the index of the left most element
    # from the array which is greater than k
    leftGreater = n

    # Finds number of elements greater than k
    while (l <= r):
        m = int(l + (r - l) / 2)
        if (arr[m] >= k):
            leftGreater = m
            r = m - 1

        # If mid element is less than
        # or equal to k update l
        else:
            l = m + 1

    # Return the count of elements
    # greater than k
    return (n - leftGreater)


# --------------------------------------------------binary------------------------------------
n=int(input())
e=len(str(n))
e1=int('7'*e)
if e1<n:
    e1=e1*10+7
tr=1
s=set()
t=e1%n
ans=len(str(e1))
while(t!=0):
    if t in s:
        tr=0
        break
    s.add(t)
    e1=t*10+7
    t=e1%n
    ans+=1
if tr==0:
    print(-1)
else:
    print(ans)

Submission status: Accepted

Solution code:
K = int(input())

if K % 2 == 0 or K % 5 == 0:
    print(-1)
    exit()
rest = 7 % K
x = rest
ans = 1
while rest:
    ans += 1
    x = x*10 % K
    rest = (rest + x) % K
print(ans)

Submission status: Accepted

Solution code:
k = int(input())
x = 7 % k
for i in range(10**6+10):
    if x == 0:
        print(i+1)
        break
    x = (10*x+7) % k
else:
    print(-1)

Submission status: Accepted

Solution code:
k = int(input())
if k%2==0 or k%5==0:
    print(-1)
    exit()
s=7
cnt=1
while s%k!=0:
    s=s%k*10+7
    cnt+=1
    #print(s)
print(cnt)

Submission status: Accepted

Solution code:
k=int(input())
if k==1:
  print(1)
  exit()
if k%2==0:
  print(-1)
  exit()
if k%5==0:
  print(-1)
  exit()
if k==7:
  print(1)
  exit()
a=7%k
for i in range(10**6+50):
  a=(a*10+7)%k
  if a==0:
    break
print(i+2)

Submission status: Accepted

Solution code:
from collections import defaultdict
import sys
mod = int(input())
d = defaultdict(int)
s = 7
c = 1
s %= mod
while(True):
    if s == 0:
        break
    if s in d:
        print(-1)
        sys.exit()
    d[s] = 1
    s = (s*10 + 7) % mod
    c += 1

print(c)

Submission status: Accepted

Solution code:
import os
import heapq
import sys
import math
import operator
from collections import defaultdict
from io import BytesIO, IOBase


"""def gcd(a,b):
    if b==0:
        return a
    else:
        return gcd(b,a%b)"""

"""def pw(a,b):
    result=1
    while(b>0):
        if(b%2==1): result*=a
        a*=a
        b//=2
    return result"""



def inpt():
    return [int(k) for k in input().split()]


def main():
    n=int(input())
    d={}
    seven=7
    q=0
    ok=True
    while(True):
        r=seven%n
        q+=1
        if(r==0):
            break
        if(r in d):
            ok=False
            break
        d[r]=True
        seven=r*10+7
    if(not ok):
        print(-1)
    else:
        print(q)

BUFSIZE = 8192


class FastIO(IOBase):
    newlines = 0

    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = "x" in file.mode or "r" not in file.mode
        self.write = self.buffer.write if self.writable else None

    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()

    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()

    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)


class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")


sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")

if __name__ == "__main__":
    main()

Submission status: Accepted

Solution code:
K = int(input())

if K % 2 == 0 or K % 5 == 0:
    print(-1)
    exit()

i = 0
A = 0
B = 7
while True:
    A += B
    A %= K
    
    B *= 10
    B %= K
    i += 1
    if A == 0:
        break
print(i)

Submission status: Accepted

Solution code:
import sys
K=int(input())
A=[0 for i in range(K)]
a=7
for i in range(K+5):
    if a%K==0:
        print(i+1)
        sys.exit()
    else:
        if A[a%K]>0:
            print(-1)
            sys.exit()
        A[a%K]+=1
        a=(a%K)*10+7

Submission status: Accepted

Solution code:
def readinput():
    k=int(input())
    return k

def main(k):
    amari=[0]*k
    r=0
    count=0
    for i in range(1,k+1):
        count+=1
        r=(10*r+7)%k
        if r==0:
            return count
        if amari[r]>0:
            return -1
        amari[r]+=1
    return -1

if __name__=='__main__':
    k=readinput()
    ans=main(k)
    print(ans)

Submission status: Accepted

Solution code:
if __name__ == '__main__':
	K = int(input())
	dls = [0] * (K+1)
	d = 7 % K
	dls[d] = 1
	c = 1
	if K % 2 == 0:
		c = -1
		d = 0
	while(d != 0):
		d = (d*10 + 7)%K
		if dls[d] == 1:
			c = -1
			break
		else:
			dls[d] = 1
			c += 1
	print(c)

Submission status: Accepted

Solution code:
def solve():
    k = int(input())
    curr_num = 7
    for count in range(1, 10 ** 6 + 100):
        if curr_num % k == 0:
            print(count)
            return
        curr_num *= 10
        curr_num += 7
        curr_num %= k
    print(-1)


if __name__ == '__main__':
    solve()

Submission status: Accepted

Solution code:

k = int(input())
count = 1
cur_remainder = 7%k
if cur_remainder==0:
    print(count)
    exit()
remainder_set=set([cur_remainder])
while True:
    cur_remainder = (cur_remainder*10+7)%k
    count += 1
    if cur_remainder==0:
        print(count)
        exit()
    if cur_remainder in remainder_set:
        print(-1)
        exit()
    remainder_set.add(cur_remainder)

Submission status: Accepted

Solution code:
import sys
readline = sys.stdin.buffer.readline
def even(n): return 1 if n%2==0 else 0

n = int(readline())
if even(n):
    print(-1)
    exit()
elif n%5==0:
    print(-1)
    exit()
s = "7"
count = 1
while True:
    if int(s) < n:
        s = s+"7"
        count += 1
        continue
    else:
        res = int(s)%n
        if res == 0:
            print(count)
            exit()
        s = str(int(s)%n)

Submission status: Accepted

Solution code:
I=lambda:list(map(int,input().split()))
k,=I()
ans=-1
s=7%k
c=0
while c<=10**6:
	c+=1
	if s==0:
		ans=c
		break
	s=(s*10+7)%k
print(ans)

Submission status: Accepted

Solution code:
K = int(input())

def solve():
    if 7 % K == 0:
        return 1

    val = 7
    for i in range(2, K + 1):
        val = val * 10 + 7
        val = val % K
        if val == 0:
            return i
    
    return -1

print(solve())

Submission status: Accepted

Solution code:
k=int(input())
if k%7==0:
    k//=7
tmp=0
for i in range(10**6+1):
    tmp=(tmp+pow(10,i,k))%k
    if tmp==0:
        print(i+1)
        exit()

print(-1)

Submission status: Accepted

Solution code:
k = int(input())
now = 7
for i in range(1, k+1):
    if int(now) % k == 0:
        print(i)
        break
    now = 10 * now + 7
    now %= k
else:
    print(-1)

Submission status: Accepted

Solution code:
k = int(input())

rem = 0
for i in range(k*10+1):
    rem = rem*10 + 7
    rem %= k
    if rem==0:
        break

if i==(k*10):
    print(-1)
else:
    print(i+1)

Submission status: Accepted

Solution code:
k = int(input())

r = 7
count = 1
found = 0
for i in range(k):
    if r % k == 0:
        print(count)
        found = 1
        break
    r = (10 * r + 7) % k
    count += 1
if found == 0:
    print(-1)

Submission status: Accepted

Solution code:
n=int(input())*9
# lis=list(map(int,input().split()))

vis={}
flag=1
a=1
t=10
while((7*(t))%n not in vis):
	k=(7*(t))%n
	vis[k]=1
	if(k==7):
		flag=0
		print(a)
		break
	a+=1
	t=(t*10)%n
	# print(k)
if(flag):
	print(-1)

Submission status: Accepted

Solution code:
def main():
    k = int(input())
    a = 7
    c = 1
    b = 7
    if k == 2 or k == 5:
        print(-1)
        exit()
    while True:
        if a%k== 0:
            print(c)
            break
        else:
            b = (b*10)%k
            a = b+a
            a = a %k
            c += 1
            if c > k:
                print(-1)
                exit()

main()

Submission status: Accepted

Solution code:
k = int(input())

num = 0
res = 0
cnt = [0] * k
while True:
    num = (num * 10 % k + 7) % k
    res += 1

    if num == 0:
        print(res)
        break

    if cnt[num] == 1:
        print(-1)
        break

    cnt[num] += 1

Submission status: Accepted

Solution code:
import sys


def main():
    input = sys.stdin.buffer.readline
    k = int(input())
    s = set()
    i = 1
    a = 7
    while True:
        a %= k
        if a in s:
            print(-1)
            break
        if a == 0:
            print(i)
            break
        s.add(a)
        i += 1
        a = 10 * a + 7


if __name__ == "__main__":
    main()

Submission status: Accepted

Solution code:
K = int(input())


def check(k):
    if k & 1 == 0:
        return -1
    if k % 7 == 0:
        k //= 7

    a = 1

    for i in range(k + 1):
        if a % k == 0:
            return i + 1
        else:
            a = (10 * a + 1) % k

    return -1


print(check(K))

Submission status: Accepted

Solution code:
K = int(input())
L = [False]*K
X = 7
ans = 0
R = 0
while not L[0]:
    ans += 1
    X %= K
    R = (R+X)%K
    X *= 10
    if L[R]:
        ans = -1
        break
    L[R] = True
    

print(ans)

Submission status: Accepted

Solution code:
k = int(input())

if k % 5 == 0 or k % 2 == 0:
  print(-1)
  exit()

n = 7 % k
m = 70 % k
ans = 1
while True:
  if n == 0:
    print(ans)
    break
  
  n += m
  n %= k
  m *= 10
  m %= k
  ans += 1

Submission status: Accepted

Solution code:
#template
def inputlist(): return [int(j) for j in input().split()]
#template
K = int(input())
if K % 2 == 0:
    print(-1)
    exit()
s = 7
for i in range(K):
    if s % K == 0:
        print(i+1)
        exit()
    if s % K != s:
        s = 10*(s%K) + 7
        continue
    s = 10*s + 7
print(-1)

Submission status: Accepted

Solution code:
K = int(input())

cnt = 1
num = 7 % K

flag = False

if num == 0:
    flag = True

remainderList = {num}

while not flag:
    cnt += 1
    
    num = ((num * 10) % K + 7) % K
    if num == 0:
        flag = True
        break
    if num in remainderList:
        break
    remainderList.add(num)

if flag:
    print(cnt)
else:
    print("-1")

Submission status: Accepted

Solution code:
K = int(input())

S = set()
cnt,n = 1,7
nothing = False

while True:
    if n % K == 0:
        print(cnt)
        break
    else:
        if n in S:
            print(-1)
            break
        else:
            S.add(n)
            n += (7 * pow(10,cnt,K))
            n %= K
            cnt += 1

Submission status: Accepted

Solution code:
#import numpy as np
#import math
#from decimal import *
#from numba import njit

#@njit
def main():
    K = int(input())

    rest = [False]*K
    a = 7
    count = 1
    while a < K:
        a = 10*a+7
        count += 1
    r = a % K
    while r != 0:
        if rest[r-1]:
            print(-1)
            return
        else:
            rest[r-1] = True
            a = 10*r+7
            count += 1
            r = a % K
    print(count)
    
main()

Submission status: Accepted

Solution code:
import sys

input = sys.stdin.readline


def main():
    K = int(input())

    num = 0
    for i in range(1, 10 ** 7 // 2):
        num = ((num * 10) + 7) % K
        if num == 0:
            ans = i
            break

    else:
        ans = -1

    print(ans)


if __name__ == "__main__":
    main()

Submission status: Accepted

Solution code:
N = int(input())

if N%2 == 0 or N == 5:
    print(-1)
    quit()
    
temp = 7%N
ans = 1
while temp != 0:
    temp = (temp*10+7)%N
    ans += 1
    if ans >= 10**6+1000:
        print(-1)
        quit()
print(ans)

Submission status: Accepted

Solution code:
import math
K = int(input())
if K == 7 or K == 1:
  print(1)
elif math.gcd(K,10) != 1:
  print(-1)
else:
  if K % 7 == 0:
    K //= 7
  cnt = 1
  res = 10
  while True:
    cnt += 1
    res *= 10
    res %= (9 * K)
    if res == 1:
      break
  print(cnt)

Submission status: Accepted

Solution code:
import sys
K = int(input())

if K%2 == 0 or K%5 == 0:
    print(-1)
    sys.exit()

dp = 7
ans = 1

while(ans <= 10000000):
    if dp % K == 0:
        print(ans)
        sys.exit()
    ans += 1
    dp = (dp * 10 + 7) % K

Submission status: Accepted

Solution code:
import sys
import bisect
from functools import lru_cache
from collections import defaultdict
inf = float('inf')
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10**6)
def input(): return sys.stdin.readline().rstrip()
def read():
  return int(readline())
def reads():
  return map(int, readline().split())
K=read()
mod=7%K
index=1
dic=defaultdict(int)
while(True):
    if mod==0:
        print(index)
        exit()
    if dic[mod]==1:
        print(-1)
        exit()
    dic[mod]=1
    mod=mod*10+7
    mod%=K
    index+=1

Submission status: Accepted

Solution code:
k = int(input())
n = 0
for i in range(k+1):
    n += pow(10, i, k)*7
    n %= k
    if n==0:
        print(i+1)
        break
else:
    print(-1)

Submission status: Accepted

Solution code:
k=int(input())
if k%2<1 or k%5<1:
  print(-1)
  exit()
a=1
t=7
m=0
while 1:
  t=t*10%k
  m+=t
  if m%k: a+=1
  else: break
print(a)

Submission status: Accepted

Solution code:
def main():
    k = int(input())
    tbl = {}
    v = int(0)
    cnt = 0
    while True:
        cnt += 1
        v = 10 * v + 7
        v = v % k

        if v == 0:
            print(cnt)
            break
        elif v in tbl.keys():
            print('-1')
            break
        else:
            tbl[v] = 0


if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
K = int(input())
A = 7 % K
X = 7 % K
n = 1
f = 0
while A != 0:
  X = (X * 10) % K
  A = (A + X) % K
  n += 1
  if n > K:
    print(-1)
    f = 1
    break
if f == 0:
  print(n)

Submission status: Accepted

Solution code:
import sys
k=int(input())
n=7
if k%2==0:
    print(-1)
    sys.exit()
for i in range(1,k+1):
    if n%k==0:
        print(i)
        sys.exit()
    else:
        n=(10*(n%k)+7)%k
print(-1)