[Python] 백준 <9663-N-Queen>

https://www.acmicpc.net/problem/9663

 

import sys
input = sys.stdin.readline

N = int(input())

ans = 0
row = [0]*N

def is_promising(x):
    for i in range(x):
        if row[x] == row[i] or abs(row[x] - row[i]) == abs(x - i):
            return False
    return True

def n_queens(x):
    global ans
    if x == N:
        ans += 1
        return

    else:
        for i in range(N):
            # [x, i]에 퀸을 놓음    
            row[x] = i
            if is_promising(x):
                n_queens(x+1)

n_queens(0)
print(ans)