Problem:


Score : 200 points

Problem Statement

Given is a sequence of N integers A_1, \ldots, A_N.

Find the (multiplicative) inverse of the sum of the inverses of these numbers, \frac{1}{\frac{1}{A_1} + \ldots + \frac{1}{A_N}}.

Constraints

1 \leq N \leq 100

1 \leq A_i \leq 1000

Input

Input is given from Standard Input in the following format:

N
A_1 A_2 \ldots A_N

Output

Print a decimal number (or an integer) representing the value of \frac{1}{\frac{1}{A_1} + \ldots + \frac{1}{A_N}}.

Your output will be judged correct when its absolute or relative error from the judge's output is at most 10^{-5}.

Sample Input 1

2
10 30

Sample Output 1

7.5

\frac{1}{\frac{1}{10} + \frac{1}{30}} = \frac{1}{\frac{4}{30}} = \frac{30}{4} = 7.5.

Printing 7.50001, 7.49999, and so on will also be accepted.

Sample Input 2

3
200 200 200

Sample Output 2

66.66666666666667

\frac{1}{\frac{1}{200} + \frac{1}{200} + \frac{1}{200}} = \frac{1}{\frac{3}{200}} = \frac{200}{3} = 66.6666....

Printing 6.66666e+1 and so on will also be accepted.

Sample Input 3

1
1000

Sample Output 3

1000

\frac{1}{\frac{1}{1000}} = 1000.

Printing +1000.0 and so on will also be accepted.



Sample input:
2
10 30


Sample output:
7.5

Submission status: Accepted

Solution code:
N = int(input())
A = [int(i) for i in input().split()]
ans = 0
for a in A:
    ans += 1/a
print(1/ans)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int,input().split()))
count = 0
for i in range(n):
    count = count + 1/a[i]
print(1/count)

Submission status: Accepted

Solution code:
N = int(input())
a = list(map(int, input().split()))

ans = 0
for i in range(N):
    ans += 1/a[i]

print(1/ans)

Submission status: Accepted

Solution code:
n=int(input())
a=list(map(int, input().split()))

a_sum=0
for i in range(n):
    a_sum+=1/a[i]
print(1/a_sum)

Submission status: Accepted

Solution code:
N = int(input())
a_array = map(int,input().split())

a_sum = 0
for a in a_array:
    a_sum += (1/a)

print(1/a_sum)

Submission status: Accepted

Solution code:
n=int(input())
a=list(map(int,input().split()))
print(1/sum(1/a[i] for i in range(n)))

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))
s = 0.0
for a in A:
  s += 1/a
print(1/s)

Submission status: Accepted

Solution code:
def main(sample_file = ''):

    """ convenient functions
    # for i, a in enumerate(iterable)
    # q, mod = divmod(a, b)
    # divmod(x, y) returns the tuple (x//y, x%y)
    # Higher-order function: reduce(operator.mul, xyz_count, 1)
    # manage median(s) using two heapq https://atcoder.jp/contests/abc127/tasks/abc127_f
    """

    """convenient decorator
    # @functools.lru_cache():
    # to facilitate use of recursive function
        # ex:
        # from functools import lru_cache
        # import sys
        # sys.setrecursionlimit(10**9)
        # @lru_cache(maxsize=None)
        # def fib(n):
        #     if n < 2:
        #         return n
        #     return fib(n-1) + fib(n-2)
        # print(fib(1000))
    """
    
    # import numpy as np
    import sys
    sys.setrecursionlimit(10**7)
    from itertools import accumulate, combinations, permutations, product # https://docs.python.org/ja/3/library/itertools.html
    # accumulate() returns iterator! to get list: list(accumulate())
    from math import factorial, ceil, floor, sqrt
    def factorize(n):
        """return the factors of the Arg and count of each factor
        
        Args:
            n (long): number to be resolved into factors
        
        Returns:
            list of tuples: factorize(220) returns [(2, 2), (5, 1), (11, 1)]
        """
        fct = []  # prime factor
        b, e = 2, 0  # base, exponent
        while b * b <= n:
            while n % b == 0:
                n = n // b
                e = e + 1
            if e > 0:
                fct.append((b, e))
            b, e = b + 1, 0
        if n > 1:
            fct.append((n, 1))
        return fct
    def combinations_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        # TODO: How should I do when n - r is negative?
        if n < 0 or r < 0:
            raise Exception('combinations_count(n, r) not defined when n or r is negative')
        if n - r < r: r = n - r
        if r < 0: return 0
        if r == 0: return 1
        if r == 1: return n
        numerator = [n - r + k + 1 for k in range(r)]
        denominator = [k + 1 for k in range(r)]
        for p in range(2,r+1):
            pivot = denominator[p - 1]
            if pivot > 1:
                offset = (n - r) % p
                for k in range(p-1,r,p):
                    numerator[k - offset] /= pivot
                    denominator[k] /= pivot
        result = 1
        for k in range(r):
            if numerator[k] > 1:
                result *= int(numerator[k])
        return result
    def combinations_with_replacement_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items allowing individual elements to be repeated more than once.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        if n < 0 or r < 0:
            raise Exception('combinations_with_replacement_count(n, r) not defined when n or r is negative')
        elif n == 0:
            return 1
        else:
            return combinations_count(n + r - 1, r)
    from bisect import bisect_left, bisect_right
    from collections import deque, Counter, defaultdict # https://docs.python.org/ja/3/library/collections.html#collections.deque
    from heapq import heapify, heappop, heappush, heappushpop, heapreplace,nlargest,nsmallest # https://docs.python.org/ja/3/library/heapq.html
    from copy import deepcopy, copy # https://docs.python.org/ja/3/library/copy.html
    import operator
    from operator import itemgetter #sort 
    # ex1: List.sort(key=itemgetter(1))
    # ex2: sorted(tuples, key=itemgetter(1,2))
    from functools import reduce, lru_cache
    def chmin(x, y):
        """change minimum
        if x > y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current minimum value
            y (long): potential minimum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x > y:
            x = y
            return (x, True)
        else:
            return (x, False)
    def chmax(x, y):
        """change maximum
        if x < y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current maximum value
            y (long): potential maximum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x < y:
            x = y
            return (x, True)
        else:
            return (x, False)

    from fractions import gcd # Deprecated since version 3.5: Use math.gcd() instead.
    def gcds(numbers):
        return reduce(gcd, numbers)
    def lcm(x, y):
        return (x * y) // gcd(x, y)
    def lcms(numbers):
        return reduce(lcm, numbers, 1)
    def make_divisors(n, reversed=False):
        """create list of divisors
        
        Args:
            number (int): number from which list of divisors is created
            reversed (bool, optional): ascending order if False. Defaults to False.
        
        Returns:
            list: list of divisors
        """
        divisors = set()
        for i in range(1, int(n**0.5)+1):
            if n % i == 0:
                divisors.add(i)
                divisors.add(n//i)
        return sorted(list(divisors),reverse=reversed)
    
    # first create factorial_list
    # fac_list = mod_factorial_list(n)
    INF = 10 ** 18
    MOD = 10 ** 9 + 7
    modpow = lambda a, n, p = MOD: pow(a, n, p) # Recursive function in python is slow!
    def modinv(a, p = MOD):
        # evaluate reciprocal using Fermat's little theorem:
        # a**(p-1) is identical to 1 (mod p) when a and p is coprime
        return modpow(a, p-2, p)
    def modinv_list(n, p = MOD):
        if n <= 1:
            return [0,1][:n+1]
        else:
            inv_t = [0,1]
            for i in range(2, n+1):
                inv_t += [inv_t[p % i] * (p - int(p / i)) % p]
            return inv_t
    def modfactorial_list(n, p = MOD):
        if n == 0:
            return [1]
        else:
            l = [0] * (n+1)
            tmp = 1
            for i in range(1, n+1):
                tmp = tmp * i % p
                l[i] = tmp
            return l
    def modcomb(n, k, fac_list = [], p = MOD):
        # fac_list = modfactorial_list(100)
        # print(modcomb(100, 5, modfactorial_list(100)))
        from math import factorial
        if n < 0 or k < 0 or n < k: return 0
        if n == 0 or k == 0: return 1
        if len(fac_list) <= n:
            a = factorial(n) % p
            b = factorial(k) % p
            c = factorial(n-k) % p
        else:
            a = fac_list[n]
            b = fac_list[k]
            c = fac_list[n-k]
        return (a * modpow(b, p-2, p) * modpow(c, p-2, p)) % p
    def modadd(a, b, p = MOD):
        return (a + b) % MOD
    def modsub(a, b, p = MOD):
        return (a - b) % p
    def modmul(a, b, p = MOD):
        return ((a % p) * (b % p)) % p
    def moddiv(a, b, p = MOD):
        return modmul(a, modpow(b, p-2, p))

    class UnionFindTree:
        """union find tree class
        TODO: fix this description...
        how to use (example):
        >>  uf = UnionFindTree(N) 
        >>  if uf.find_root(a) == uf.find_root(b):
        >>      do something
        >>  else:
        >>      do something
        >>      uf.unite(a, b)
        """
        def __init__(self, N):
            self.root = [-1] * (N+1)
            self.rank   = [0]  * (N+1)
            self.connected_num = [1] * (N+1)
    
        def find_root(self,x):
            root = self.root
            while root[x] != -1:
                x = root[x]
            return x
    
        def unite(self,x,y):
            root = self.root
            rank = self.rank
            connected_num = self.connected_num
            find_root = self.find_root
    
            rx = find_root(x)
            ry = find_root(y)
            if rx != ry:
                if rank[rx] < rank[ry]:
                    root[rx] = ry
                    rx,ry = ry,rx
                else:
                    if rank[rx] == rank[ry]:
                        rank[rx] += 1
                    root[ry] = rx       
                connected_num[rx] += connected_num[ry]

    # Graph: https://en.wikipedia.org/wiki/Directed_graph
    # Bellman-Ford: O(|V||E|). Use this if there exists an edge with negative length in the graph
    # After N steps, the shortest path has converded if there doesn't exist an cycle of edges with negative
    # Watch out: d[N] == d[2*N] doesn't necessarily mean the graph doesn't have negative cycle
    # ref: https://www.youtube.com/watch?v=1Z6ofKN03_Y

    def BellmanFord(N, M, ABC, vertex_start, vertex_end, value_if_inf = -1, find_shortest = False):
        """to calculate furthest or shortest length between vertex_start and vertex_end using BellmanFord algorithm
        
        Args:
            N (int): number of vertices
            M (int): number of edges
            ABC (list): [(ai, bi, ci) for _ in range(N)] where i-th edge is directed from vertex ai to vertex bi and the length is ci 
            vertex_start (int): start vertex. usually use 0.
            vertex_end (int): end vertex. usually use N-1.
            value_if_inf (int or string as you like, optional): value you want when the furthest (or shortest) distance is infinite (or -infinite). Defaults to -1.
            find_shortest (bool, optional): choose False to find furthest path. Defaults to False.
        
        Returns:
            int or string: normally int (but can be str if you set value_if_inf to str)
            
        Example:
                N, M, P = R()
                ABC = [R() for _ in range(M)]
                ABC = [(a-1, b-1, c-P) for a, b, c in ABC]
                print(BellmanFord(N, M, ABC, 0, N-1, value_if_inf = 'inf'))

        """

        def make_reachable_list(N, M, ABC, vertex_start, vertex_end):
            reachable_to_direct = defaultdict(list)
            reachable_from_direct = defaultdict(list)
            reachable_from_start = [False] * N
            reachable_to_end = [False] * N
            reachable_from_start[vertex_start] = True
            reachable_to_end[vertex_end] = True
            reachable_from_both_sides = [False] * N
            dfs_from_start = []
            dfs_to_end = []
            for a, b, c in ABC:
                reachable_to_direct[a].append(b)
                reachable_from_direct[b].append(a)
                if a == vertex_start:
                    dfs_from_start.append(b)
                    reachable_from_start[b] = True
                if b == vertex_end:
                    dfs_to_end.append(a)
                    reachable_to_end[a] = True
            while dfs_from_start:
                v = dfs_from_start.pop()
                for i in reachable_to_direct[v]:
                    if not reachable_from_start[i]:
                        reachable_from_start[i] = True
                        dfs_from_start.append(i)
            while dfs_to_end:
                v = dfs_to_end.pop()
                for i in reachable_from_direct[v]:
                    if not reachable_to_end[i]:
                        reachable_to_end[i] = True
                        dfs_to_end.append(i)
            for i in range(N):
                reachable_from_both_sides[i] = reachable_from_start[i] and reachable_to_end[i]
            return reachable_from_both_sides
        
        reachable_from_both_sides = make_reachable_list(N, M, ABC, vertex_start, vertex_end)
        
        if find_shortest:
            dist = [INF for i in range(N)]
        else:
            dist = [-INF for i in range(N)]
        
        dist[vertex_start] = 0
        for i in range(N):
            updated = False
            for a, b, c in ABC:
                if not reachable_from_both_sides[a]:
                    continue
                elif find_shortest:
                    update_condition = dist[a] + c < dist[b]
                else:
                    update_condition = dist[a] + c > dist[b]
                if dist[a] != INF and update_condition:
                    dist[b] = dist[a] + c
                    updated = True
                    if i == N-1:
                        return value_if_inf
            if not updated:
                break
        return dist[vertex_end]

    """ initialize variables and set inputs
    # initialize variables
        # to initialize list, use [0] * n
        # to initialize two dimentional array, use [[0] * N for _ in range(N)]
    # set inputs
        # put inputs between specific values (almost as quickly)
        # ex) S = [-INF] + [int(r()) for _ in range(A)] + [INF]
        # open(0).read() is sometimes useful:
        # ex) n, m, *x = map(int, open(0).read().split())
        #     min(x[::2]) - max(x[1::2])
        # ex2) *x, = map(int, open(0).read().split())
        #     don't forget to add comma after *x if only one variable is used
    # preprocessing
        # transpose = [x for x in zip(*data)]
        # ex) [[1, 2, 3], [4, 5, 6], [7, 8, 9]] => [(1, 4, 7), (2, 5, 8), (3, 6, 9)]
        # flat = [flatten for inner in data for flatten in inner]
        # ex) [[1, 2, 3], [4, 5, 6], [7, 8, 9]] => [1, 2, 3, 4, 5, 6, 7, 8, 9]
    # calculate and output
        # output pattern
        # ex1) print(*l) => when l = [2, 5, 6], printed 2 5 6
    """

    # functions to read input
    r = lambda: sys.stdin.readline().strip()
    r_int = lambda: int(r())
    R = lambda: list(map(int, r().split()))
    Rmap = lambda: map(int, r().split())
    Rfloat = lambda: list(map(float, r().split()))
    Rtuple = lambda: tuple(map(int, r().split()))

    """ how to treat input
    # single int: int(r())
    # single string: r()
    # single float: float(r())
    # line int: R()
    # line string: r().split()
    # line (str, int, int): [j if i == 0 else int(j) for i, j in enumerate(r().split())]
    # lines int: [R() for _ in range(n)]
    """

    # for test
    if sample_file:
        sys.stdin = open(sample_file)
        
    # ----------------------------------
    # main

    N = int(r())
    A = R()
    ans = 0
    for a in A:
        ans += 1/a
    print(1/ans)
    
    
    

    # to finish code, use return instead of exit()
    # end of main
    # ----------------------------------

    """memo: how to use defaultdict of list
    # initialize
    Dic = defaultdict(list)
    # append / extend
    Dic[x].append(y)
    # three methods for loop: keys(), values(), items()
    for k, v in Dic.items():
    """
    
    """memo: how to solve binary problems
    # to make binary digits text
    >>> a = 5
    >>> bin_str_a = format(a, '#06b')
    >>> print(bin_str_a)
    0b0101 # first 2 strings (='0b') indicates it is binary
    """
    
    """memo: how to solve the problem
    creating simple test/answer
    greed
    simple dp
    graph
    """

if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
from functools import reduce
from operator import mul

n = int(input())
a = list(map(int, input().split()))

p = reduce(mul, a)

y = 0
for aa in a:
    y += p // aa

print(p / y)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int,input().split()))

q = 0
for a in A :
    q += 1/a

print(1/q)

Submission status: Accepted

Solution code:
N = int(input())
A = [int(i) for i in input().split()]

s = 0
for a in A:
    s += 1/a
print(1/s)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))
r = 0
for i in a:
    r += (1/i)
ans = 1/r
print(ans)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))
b = [0]*n
for i in range(n):
    b[i]=1/a[i]
print(1/sum(b))

Submission status: Accepted

Solution code:
import sys
def get_array(): return list(map(int , sys.stdin.readline().strip().split()))
def get_ints(): return map(int, sys.stdin.readline().strip().split())
def input(): return sys.stdin.readline().strip()

n=int(input())
Arr=get_array()
total=0
for i in Arr:
  total+=(1/i)
ans=1/total
print(ans)

Submission status: Accepted

Solution code:
N = int(input())
a = list(map(int, input().split()))
tmp = 1
for i in range(N):
    tmp *= a[i]

s = 0
for i in range(N):
    s += tmp // a[i]

print(tmp / s)

Submission status: Accepted

Solution code:
N = int(input().strip())
A = list(map(int, input().strip().split()))

b = 0
for a in A: b += 1 / a

print(1 / b)

Submission status: Accepted

Solution code:
from sys import stdin
N = int(stdin.readline().rstrip())
data = [int(x) for x in stdin.readline().rstrip().split()]
ans = 0
for i in data:
    ans += (1/i)
print(1/ans)

Submission status: Accepted

Solution code:
n = int(input())
A = list(map(int, input().split()))
ans = 0

for i in range(n):
    ans += 1/A[i]

ans = 1/ans
print(ans)

Submission status: Accepted

Solution code:
N = input()
A = map(float, raw_input().split())

print "%.10f"%(1/sum(1/a for a in A))

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))

sum_Ainv = 0
ans = 0

for i in range(N):
    sum_Ainv += (1 / A[i])

ans = 1 / sum_Ainv

print(ans)

Submission status: Accepted

Solution code:
import sys
input = sys.stdin.readline

def main():
  n = int(input())
  alist = list(map(int, input().split()))
  ans = 0
  for a in alist:
    ans += 1/a
  print('%.10f' % (1/ans))


if __name__ == '__main__':
  main()

Submission status: Accepted

Solution code:
n = int(input())
ls = list(map(lambda x: 1/int(x), input().split()))
print(1/sum(ls))

Submission status: Accepted

Solution code:
import sys, re, os
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians
from itertools import permutations, combinations, product, accumulate
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from fractions import gcd
 
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def S_MAP(): return map(str, input().split())
def LIST(): return list(map(int, input().split()))
def S_LIST(): return list(map(str, input().split()))

sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

n = INT()
A = LIST()
s = 0
for a in A:
    s += (1/a)
print(1/s)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int,input().split()))

b = 0
for i in range(n):
    b += 1/a[i]

print(1/b)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))

total = 0
for a in A:
    total += 1/a

print(1/total)

Submission status: Accepted

Solution code:
n = int(input())
nums =  list(map(int, input().split() ))

ans = 0
for i in range(n):
	ans += 1 / nums[i]
ans = 1 / ans
print(ans)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int,input().split()))
s = 1
for i in range(N):
    s *= A[i]
su = 0
for i in range(N):
    su += s//A[i]
print(s/su)

Submission status: Accepted

Solution code:
N = int(input())
a = list(map(int, input().split()))

b = []
for i in range(N):
    b.append(1/a[i])

print(1/sum(b))

Submission status: Accepted

Solution code:
#!/usr/bin/env python3
n = int(input())
a = list(map(int, input().split()))
p = 1
for x in a:
    p *= x
s = 0
for x in a:
    s += p // x
print(p / s)

Submission status: Accepted

Solution code:
N = int(input())

A = list(map(int, input().split()))

tmp = 0

for i in range(len(A)):
    tmp += (1/A[i])

print(1/tmp)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))
s = sum(map(lambda x:1 / x, a))
print(1 / s)

Submission status: Accepted

Solution code:
n = int(input())
A = list(map(int, input().split()))

t = 0
for i in range(n):
    t += 1/A[i]

print(1/t)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int,input().split()))

print(1/sum(1/a for a in A))

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))
ans = 0
for i in range(N):
    ans += 1/A[i]

print(1/ans)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))
s = 0
for x in a:
    s += 1 / x
print(1 / s)

Submission status: Accepted

Solution code:
import sys
sys.setrecursionlimit(10**7)
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x) - 1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def II(): return int(sys.stdin.readline())
def SI(): return sys.stdin.readline().strip()
INF = 10 ** 18
MOD = 10 ** 9 + 7

debug = True
#debug = False

def dprint(*objects):
    if debug == True:
        print(*objects)

def solve():
    N = II()
    a_list = LI()

    ans = 0
    for a in a_list:
        ans += 1/a
    print(1/ans)

solve()

Submission status: Accepted

Solution code:
# 2019/08/18
# AtCoder Beginner Contest 138 - B

# Input
n = int(input())
a = list(map(int,input().split()))

sum = 0
# Calc
for i in range(n):
    sum = sum + (1 / a[i])

ans = 1 / sum

# Output
print(ans)

Submission status: Accepted

Solution code:
input()

a=list(map(int,input().split()))

s=0
for it in a:
    s+=1/it
print(1/s)

Submission status: Accepted

Solution code:
# -*- coding: utf-8 -*-
import sys
import math
from bisect import bisect_left
from bisect import bisect_right
import collections
import copy
import heapq
from collections import defaultdict
from heapq import heappop, heappush
import itertools
input = sys.stdin.readline

##### リストの 二分木検索 #####
# bisect_left(lists, 3)
# bisect_right(lists, 3)

##### プライオリティキュー #####
# heapq.heapify(a) #リストaのheap化
# heapq.heappush(a,x) #heap化されたリストaに要素xを追加
# heapq.heappop(a) #heap化されたリストaから最小値を削除＆その最小値を出力

# heapq.heappush(a, -x) #最大値を取り出す時は、pushする時にマイナスにして入れよう
# heapq.heappop(a) * (-1) #取り出す時は、-1を掛けて取り出すこと

##### タプルリストのソート #####
# sorted(ans) #(a, b) -> 1st : aの昇順, 2nd : bの昇順
# sorted(SP, key=lambda x:(x[0],-x[1])) #(a, b) -> 1st : aの昇順, 2nd : bの降順
# sorted(SP, key=lambda x:(-x[0],x[1])) #(a, b) -> 1st : aの降順, 2nd : bの昇順
# sorted(SP, key=lambda x:(-x[0],-x[1])) #(a, b) -> 1st : aの降順, 2nd : bの降順

# sorted(SP, key=lambda x:(x[1])) #(a, b) -> 1st : bの昇順
# sorted(SP, key=lambda x:(-x[1])) #(a, b) -> 1st : bの降順

def inputInt(): return int(input())
def inputMap(): return map(int, input().split())
def inputList(): return list(map(int, input().split()))

def main():
	N = inputInt()
	A = inputList()

	ans = 0
	for i in A:
		tmp = 1/i
		ans += tmp

	print(1/ans)


if __name__ == "__main__":
	main()

Submission status: Accepted

Solution code:
#!/usr/bin/env python3
#ABC138 B

import sys
import math
import bisect
sys.setrecursionlimit(1000000000)
from heapq import heappush, heappop,heappushpop
from collections import defaultdict
from itertools import accumulate
from collections import Counter
from collections import deque
from operator import itemgetter
from itertools import permutations
mod = 10**9 + 7
inf = float('inf')
def I(): return int(sys.stdin.readline())
def LI(): return list(map(int,sys.stdin.readline().split()))

n = I()
a = LI()
x = 1
for i in range(n):
    x *= a[i]
s = []
for i in range(n):
    s.append(x//a[i])
print(x/sum(s))

Submission status: Accepted

Solution code:
n = int(input())
dat = list(map(int, input().split()))
res = 0
for i in range(len(dat)):
    res += 1 / dat[i]
res = 1 / res
print(res)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))
sum = 0

for i in a:
    sum += 1/i

print(1/sum)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int,input().split()))

inv = 0
for a in A:
    inv += 1/a
res = 1/inv
print(res)

Submission status: Accepted

Solution code:
N = int(input())
A = [int(i) for i in input().split()]

ans = 0
for i in range(N):
    ans += 1/A[i]

print(1/ans)

Submission status: Accepted

Solution code:
N=int(input())
A=list(map(int,input().split()))

sum=0
for a in A:
    sum += 1.0 / a

ans = 1.0 / sum
print(ans)

Submission status: Accepted

Solution code:
import math
import sys
import queue
from collections import Counter
from itertools import accumulate
from fractions import gcd
from functools import reduce


def lcm(a, b):
    return a * b // gcd(a, b)

def combination_count(n, r):
    return math.factorial(n) // (math.factorial(n - r) * math.factorial(r))

def permutations_count(n, r):
    return math.factorial(n) // math.factorial(n - r)

sys.setrecursionlimit(10000)

mod = 1000000007

"""
# 0埋め, 小数点出力桁指定時のときの出力
a = 100
b = 0.987654321
print("{0:06d}-{1:6f}".format(a,b))
000100-0.987654

# 文字列をリストに格納
char_list = list("abcd") # ["a","b","c","d"]

# 標準入力取得
## 文字列
    = sys.stdin.readline().rstrip()
    = list(sys.stdin.readline().rstrip())

## 数値
    = int(sys.stdin.readline())
    = map(int, sys.stdin.readline().split())
    = list(map(int, sys.stdin.readline().split()))
    = [list(map(int,list(sys.stdin.readline().split()))) for i in range(N)]
"""

if __name__ == "__main__":
    N = int(sys.stdin.readline())
    L = list(map(int, sys.stdin.readline().split()))
    B = 0
    for l in L:
        B +=  1 / l

    print(1 / B)

Submission status: Accepted

Solution code:
def sol():
    N = int(input())
    A = list(map(int, input().split()))

    prod = 1
    for a in A:
        prod *= a

    b = 0
    for a in A:
        b += prod // a
    
    ans = prod / b
    print(ans)

sol()

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))
total = 0
for num in A:
    total += 1 / num

print(1 / total)

Submission status: Accepted

Solution code:
# お約束
INF = float("inf")
MOD = int(1e9 + 7)
def int1(n):
    return int(n) - 1
def parse(*args):
    # (tuple(map(int, input().split())) for _ in range(N))
    return tuple(p(v) for p, v in zip(args, input().split()))

N = int(input())
A = list(map(int, input().split()))

res = 0
for a in A:
	res += 1 / a
print(1 / res)

Submission status: Accepted

Solution code:
n = int(input())
aa = list(map(int, input().split()))

s = 0
for a in aa:
    s += 1.0 / a
s = 1.0 / s
print(s)

Submission status: Accepted

Solution code:
n = int(input())
A = [int(i) for i in input().split()]

f = float(0)
for a in A:
    f += 1/a
print(1/f)

Submission status: Accepted

Solution code:
n = int(input())
l = list(map(int, input().split()))

sum = 0
for a in l:
    sum += 1/a

print(1/sum)

Submission status: Accepted

Solution code:
n=int(input())
lst=list(map(int, input().split()))
s=0
for e in lst:
  s+=1/e
print(1/s)

Submission status: Accepted

Solution code:
from sys import stdin

N = int(stdin.readline().rstrip())
A = [int(x) for x in stdin.readline().rstrip().split()]

ans = 0
for a in A:
    ans += 1 / a


print(1 / ans)

Submission status: Accepted

Solution code:
#import sys
#input = sys.stdin.readline
def main():
    N = int( input())
    A = list( map( int, input().split()))
    now = 1
    for a in A:
        now *= a
    ans = now
    q = 0
    for a in A:
        q += now//a
    print(ans/q)
if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split(" ")))
print(1 / sum(1 / a for a in A))

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))
print(1 / sum(1/A[i] for i in range(N)))

Submission status: Accepted

Solution code:
n = int(input())
l = list(map(int, input().split()))

ans = 0
for a in l:
  ans += 1/a
ans = 1/ans

print(ans)

Submission status: Accepted

Solution code:
n = int(input())
a_list = [int(i) for i in input().split()]

x = 0

for a in a_list:
    x += 1/a

print(1/x)

Submission status: Accepted

Solution code:
n = int(input())
a = [int(i) for i in input().split()]
re = 0
for i in range(n):
    re += 1/a[i]
print(1/re)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int,input().split()))
B = 1
for i in range(N): B*=A[i]
C = 0
for i in range(N): C+=(B/A[i])
print(B/C)

Submission status: Accepted

Solution code:
#!/usr/bin/env python
# coding: utf-8

def ri():
    return int(input())

def rl():
    return list(input().split())

def rli():
    return list(map(int, input().split()))

def main():
    n = ri()
    la = rli()
    rev = sum(1/a for a in la)
    print(1/rev)


if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))

ans = 0

for i in a:
    ans += 1/i
    
print(1/ans)

Submission status: Accepted

Solution code:
n = int(input())
a = list(map(int, input().split()))

cnt = 0
for i in range(n):
    cnt += 1 / a[i]
print(1/cnt)

Submission status: Accepted

Solution code:
N = int(input())
A = list(map(int, input().split()))

bunbo = 0
for i in range(N):
  bunbo += 1 / A[i]
print(1 / bunbo)