IP
121.168.0.0
Created
05-20 12:45
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import java.io.*;
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class Main{
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static boolean[][] chess;
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static int n,res=0;
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static void queen(int y,int x){
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chess[y][x]=true;
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int i=y+1,j;
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for(;i<n;i++){
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chess[i][x]=true; //세로
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}
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i=y+1; j=x-1;
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while(!(i>=n||j<0)){ //대각선 왼아래
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chess[i++][j--]=true;
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}
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i=y+1; j=x+1;
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while(!(i>=n||j>=n)){ //대각선 오아래
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chess[i++][j++]=true;
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}
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}
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static boolean[][] cp(int y,int x){
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boolean[][] copy=new boolean[n][3];
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int i=y,j,id=0;
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for(;i<n;i++){
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copy[id++][0]=chess[i][x]; //세로
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}
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i=y;j=x;id=0;
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while(!(i>=n||j<0)){ //대각선 왼아래
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copy[id++][1]=chess[i++][j--];
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}
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i=y;j=x;id=0;
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while(!(i>=n||j>=n)){ //대각선 오아래
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copy[id++][2]=chess[i++][j++];
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}
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return copy;
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}
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static boolean[][] ch(int y,int x,boolean[][] copy){
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int i=y,j,id=0;
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for(;i<n;i++){
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chess[i][x]=copy[id++][0]; //세로
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}
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i=y;j=x;id=0;
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while(!(i>=n||j<0)){ //대각선 왼아래
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chess[i++][j--]=copy[id++][1];
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}
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i=y;j=x;id=0;
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while(!(i>=n||j>=n)){ //대각선 오아래
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chess[i++][j++]=copy[id++][2];
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}
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return copy;
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}
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static void nq(int dt){
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if(dt==n){
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res++;
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return;
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}
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for(int i=0;i<n;i++){
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if(!chess[dt][i]){
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boolean[][] copy=cp(dt,i);
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queen(dt,i);
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nq(dt+1);
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ch(dt,i,copy);
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}
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}
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}
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public static void main(String[] args)throws Exception{
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BufferedReader I=new BufferedReader(new InputStreamReader(System.in));
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n=Integer.parseInt(I.readLine());
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chess=new boolean[n][n];
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nq(0);
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System.out.println(res);
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}
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}