package main

import (
	"fmt"
)

func solveNQueens(n int) [][]string {
	solutions := make([][]string, 0)
	colNum := make([]int, n)
	colLaid := make([]bool, n)
	mainLaid := make([]bool, 2*n) // Range of row-col is [1-n, n-1], so row-col+n -> [1, 2n-1]
	viceLaid := make([]bool, 2*n)
	for row := 0; row < n; row++ { // The ith queen
		for col := 0; col < n; col++ {
			idx := row - col + n
			if colLaid[col] || mainLaid[idx] || viceLaid[idx] {
				continue
			}
			colNum[row] = col
			colLaid[col] = true
			mainLaid[idx] = true
			viceLaid[idx] = true
			break
		}
	}
	fmt.Println(colNum)
	return solutions
}

// func main() {
// 	fmt.Println(solveNQueens(4))
// }