Problem: You are given N real values A_1, A_2, \ldots, A_N. Compute the number of pairs of indices (i, j) such that i < j and the product A_i \cdot A_j is integer.

Submission attempts (in order):
#! /usr/bin/env python
# -*- coding: utf-8 -*-

#

"""
"""

from collections import defaultdict
import bisect

import sys
input = sys.stdin.readline
from decimal import *
from collections import Counter


def solve(n):
    cnt = Counter()
    n_int = 0
    for _ in range(n):
        getcontext().prec = 20
        a = input()
        da = Decimal(a)
        ia = int(da*(10**9))
        if ia%10**9 == 0:
            n_int += 1
        pmul_2 = 0
        pmul_5 = 0
        ia2 = ia
        while ((ia2 & 1) == 0 and pmul_2 < 18): 
            ia2 = ia2 >> 1
            pmul_2 += 1
        ia5 = ia
        while 1:
            if ia5 % 5 ==0:
                pmul_5 += 1
                ia5 = ia5//5
            else:
                break
        cnt[(pmul_2,pmul_5)] += 1
    ans = 0
    print(cnt)
    for pm2_1 in range(0,19):
        for pm2_2 in range(18-pm2_1,19):
            for pm5_1 in range(1,19):
                for pm5_2 in range(18-pm5_1,19):
                    ans += cnt[(pm2_1,pm5_1)]*cnt[(pm2_2,pm5_2)]
    ans -= n_int
    ans = ans//2

    print(ans)
                






def main():
    n = int(input())
    solve(n)


if __name__ == "__main__":
    main()

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

#

"""
"""

from collections import defaultdict
import bisect

import sys
input = sys.stdin.readline
from decimal import *
from collections import Counter


def solve(n):
    cnt = Counter()
    n_int = 0
    for _ in range(n):
        getcontext().prec = 22
        a = input().rstrip()
        da = Decimal(a)
        ia = int(da.shift(9))
        print(a,ia)
        if ia%10**9 == 0:
            n_int += 1
        pmul_2 = 0
        pmul_5 = 0
        ia2 = ia
        while ((ia2 & 1) == 0 and pmul_2 < 18): 
            ia2 = ia2 >> 1
            pmul_2 += 1
        ia5 = ia
        while 1:
            if (ia5 % 5 ==0 and pmul_5 < 18):
                pmul_5 += 1
                ia5 = ia5//5
            else:
                break
        cnt[(pmul_2,pmul_5)] += 1
    ans = 0
    print(cnt)
    for pm2_1 in range(0,19):
        for pm2_2 in range(18-pm2_1,19):
            for pm5_1 in range(0,19):
                for pm5_2 in range(18-pm5_1,19):
                    ans += cnt[(pm2_1,pm5_1)]*cnt[(pm2_2,pm5_2)]
    ans -= n_int
    ans = ans//2
    
    print(ans)
                






def main():
    n = int(input())
    solve(n)


if __name__ == "__main__":
    main()

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

#

"""
"""

from collections import defaultdict
import bisect

import sys
input = sys.stdin.readline
from decimal import *
from collections import Counter


def solve(n):
    cnt = Counter()
    n_int = 0
    for _ in range(n):
        getcontext().prec = 22
        a = input().rstrip()
        da = Decimal(a)
        ia = int(da.shift(9))
        print(a,ia)
        if ia%10**9 == 0:
            n_int += 1
        pmul_2 = 0
        pmul_5 = 0
        ia2 = ia
        while ((ia2 & 1) == 0 and pmul_2 < 18): 
            ia2 = ia2 >> 1
            pmul_2 += 1
        ia5 = ia
        while 1:
            if (ia5 % 5 ==0 and pmul_5 < 18):
                pmul_5 += 1
                ia5 = ia5//5
            else:
                break
        cnt[(pmul_2,pmul_5)] += 1
    ans = 0
    #print(cnt)
    for pm2_1 in range(0,19):
        for pm2_2 in range(18-pm2_1,19):
            for pm5_1 in range(0,19):
                for pm5_2 in range(18-pm5_1,19):
                    ans += cnt[(pm2_1,pm5_1)]*cnt[(pm2_2,pm5_2)]
    ans -= n_int
    ans = ans//2
    
    print(ans)
                






def main():
    n = int(input())
    solve(n)


if __name__ == "__main__":
    main()

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

#

"""
"""

from collections import defaultdict
import bisect

import sys
input = sys.stdin.readline
from decimal import *
from collections import Counter


def solve(n):
    cnt = Counter()
    n_int = 0
    for _ in range(n):
        a = input()
        da = Decimal(a)
        ex = da.as_tuple().exponent
        while ex < 0 and da.as_tuple().digits[-1] == 0:
           a = a[:-1] 
           da = Decimal(a)
           ex = da.as_tuple().exponent
        if ex == 0:
            n_int += 1
        if ex >= -4:
            ia = int(da*(10**4))
            pmul_2 = 0
            pmul_5 = 0
            ia2 = ia
            while 1:
                if ia2 % 2 ==0 and pmul_2 < 8:
                    pmul_2 += 1
                    ia2 = ia2//2
                else:
                    break
            ia5 = ia
            while 1:
                if ia5 % 5 ==0 and pmul_5 < 8:
                    pmul_5 += 1
                    ia5 = ia5//5
                else:
                    break
            cnt[(pmul_2,pmul_5)] += 1
    ans = 0
    print(cnt)
    for pm2_1 in range(0,9):
        for pm2_2 in range(8-pm2_1,9):
            for pm5_1 in range(0,9):
                for pm5_2 in range(8-pm5_1,9):
                    ans += cnt[(pm2_1,pm5_1)]*cnt[(pm2_2,pm5_2)]
    ans -= n_int
    ans = ans//2

    print(ans)
                






def main():
    n = int(input())
    solve(n)


if __name__ == "__main__":
    main()

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

#

"""
"""

from collections import defaultdict
import bisect

import sys
input = sys.stdin.readline
from decimal import *
from collections import Counter


def solve(n):
    cnt = Counter()
    n_int = 0
    for _ in range(n):
        getcontext().prec = 22
        a = input().rstrip()
        da = Decimal(a)
        ia = int(da.shift(9))
        #print(a,ia)
        if ia%10**9 == 0:
            n_int += 1
        pmul_2 = 0
        pmul_5 = 0
        ia2 = ia
        while ((ia2 & 1) == 0 and pmul_2 < 18): 
            ia2 = ia2 >> 1
            pmul_2 += 1
        ia5 = ia
        while 1:
            if (ia5 % 5 ==0 and pmul_5 < 18):
                pmul_5 += 1
                ia5 = ia5//5
            else:
                break
        cnt[(pmul_2,pmul_5)] += 1
    ans = 0
    #print(cnt)
    for pm2_1 in range(0,19):
        for pm2_2 in range(18-pm2_1,19):
            for pm5_1 in range(0,19):
                for pm5_2 in range(18-pm5_1,19):
                    ans += cnt[(pm2_1,pm5_1)]*cnt[(pm2_2,pm5_2)]
    ans -= n_int
    ans = ans//2
    
    print(ans)
                






def main():
    n = int(input())
    solve(n)


if __name__ == "__main__":
    main()

Verdicts: Wrong Answer

Wrong Answer

Wrong Answer

Wrong Answer

Accepted