Problem:


Score : 500 points

Problem Statement

We have N integers. The i-th number is A_i.

\{A_i\} is said to be pairwise coprime when GCD(A_i,A_j)=1 holds for every pair (i, j) such that 1\leq i < j \leq N.

\{A_i\} is said to be setwise coprime when \{A_i\} is not pairwise coprime but GCD(A_1,\ldots,A_N)=1.

Determine if \{A_i\} is pairwise coprime, setwise coprime, or neither.

Here, GCD(\ldots) denotes greatest common divisor.

Constraints

2 \leq N \leq 10^6

1 \leq A_i\leq 10^6

Input

Input is given from Standard Input in the following format:

N
A_1 \ldots A_N

Output

If \{A_i\} is pairwise coprime, print pairwise coprime; if \{A_i\} is setwise coprime, print setwise coprime; if neither, print not coprime.

Sample Input 1

3
3 4 5

Sample Output 1

pairwise coprime

GCD(3,4)=GCD(3,5)=GCD(4,5)=1, so they are pairwise coprime.

Sample Input 2

3
6 10 15

Sample Output 2

setwise coprime

Since GCD(6,10)=2, they are not pairwise coprime. However, since GCD(6,10,15)=1, they are setwise coprime.

Sample Input 3

3
6 10 16

Sample Output 3

not coprime

GCD(6,10,16)=2, so they are neither pairwise coprime nor setwise coprime.



Sample input:
3
3 4 5


Sample output:
pairwise coprime

Submission status: Accepted

Solution code:
import sys
import math
import collections
import bisect
import itertools
import decimal

# import numpy as np

# sys.setrecursionlimit(10 ** 6)
INF = 10 ** 20
MOD = 10 ** 9 + 7
# MOD = 998244353

ni = lambda: int(sys.stdin.readline().rstrip())
ns = lambda: map(int, sys.stdin.readline().rstrip().split())
na = lambda: list(map(int, sys.stdin.readline().rstrip().split()))
na1 = lambda: list(map(lambda x: int(x) - 1, sys.stdin.readline().rstrip().split()))


# ===CODE===


class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())


def main():
    n = ni()
    a = na()

    tmp = len(a)

    # 素数列挙
    def Eratosthenes(n):  # N以下のすべての値に対して素数を返す
        a = [[] for _ in range(n + 1)]
        if n >= 2:
            for i in range(2, n + 1):
                if len(a[i]) == 0:
                    for j in range(i, n + 1, i):
                        a[j].append(i)
        return a

    l = max(a)
    p = Eratosthenes(l)
    cnt = [0 for _ in range(l + 1)]

    pc = True
    tc = True

    for ai in a:
        for pi in p[ai]:
            cnt[pi] += 1
            if cnt[pi] >1:
                pc = False
            if cnt[pi] == n:
                tc = False
                break


    if pc:
        print("pairwise coprime")
    elif tc:
        print("setwise coprime")
    else:
        print("not coprime")

if __name__ == '__main__':
    main()

Submission status: Accepted

Solution code:
class Sieve:
    """区間[2,n]の値を素因数分解する"""

    def __init__(self, n=1):
        primes = []
        f = [0] * (n + 1)
        f[0] = f[1] = -1
        for i in range(2, n + 1):  # 素数を探す
            if f[i]:
                continue
            primes.append(i)
            f[i] = i  # 素数には自身を代入
            for j in range(i * i, n + 1, i):  # 合成数に素因数を書き込む
                if not f[j]:
                    f[j] = i  # 最小の素因数を代入
        self.primes = primes
        self.f = f

    def is_prime(self, x) -> bool:  # 素数判定
        return self.f[x] == x

    def factor_list(self, x) -> list:  # 素因数分解の昇順リスト, [2,2,3,5,...]
        res = []
        while x != 1:
            res.append(self.f[x])
            x //= self.f[x]
        return res

    def factor(self, x) -> list:  # 素因数分解の頻度リスト, [[2,x],[3,y],[5,z],...]
        fl = self.factor_list(x)
        if not fl:
            return []
        res = [[fl[0], 0]]
        for p in fl:
            if res[-1][0] == p:
                res[-1][1] += 1
            else:
                res.append([p, 1])
        return res


def main():
    N = int(input())
    *A, = map(int, input().split())

    B = [0] * (10 ** 6 + 1)
    for x in A:
        B[x] += 1

    setwise = False

    sv = Sieve(10 ** 6)
    for p in sv.primes:
        e = p
        cnt = 0
        while e <= 10 ** 6:
            if B[e]:
                cnt += B[e]
            e += p
        if cnt == N:
            print('not coprime')
            return
        elif cnt > 1:
            setwise = True

    print('setwise coprime' if setwise else 'pairwise coprime')


if __name__ == '__main__':
    main()