Submission #1518272

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Source Code Expand

import java.util.Arrays;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

/**
 * http://abc025.contest.atcoder.jp/tasks/abc025_d
 */
public class Main {

	static final int N = 5;
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int[][] f = new int[N][N];
		Set<Integer> list = new HashSet<Integer>();
		for(int i=1; i<=N*N; i++) list.add(i);
		for(int y=0; y<N; y++){
			for(int x=0; x<N; x++){
				f[y][x] = sc.nextInt();
				list.remove(f[y][x]);
			}
		}
		sc.close();
		System.out.println(getCount(f, list));
	}

	static long getCount(int[][] f, Set<Integer> list) {
		
		if(list.isEmpty()){
			return check(f) ? 1 : 0;
		}
		
		int result = 0;
		boolean find = false;
		for(int y=0; y<N; y++){
			for(int x=0; x<N; x++){
				if(f[y][x]==0){
					find = true;
					for(int n:list){				
						int[][] f2 = getCopy(f);
						Set<Integer> list2 = new HashSet<Integer>();
						f2[y][x]=n;
						for(int i:list) if(i!=n) list2.add(i);
						result += getCount(f2,list2);			
					}
					break;
				}
			}
			if(find) break;
		}
		
		return result;
	
	}
	
	static boolean check(int[][] f){
		
		//System.out.println("------------------------");
		//for(int y=0; y<N; y++) System.out.println(Arrays.toString(f[y]));
		//System.out.println("========================");

		for(int y=0; y<N; y++){
			for(int x=0; x<N-2; x++){
				int n = f[y][x];
				if(n>f[y][x+1] && f[y][x+1]>f[y][x+2]) return false;
				if(n<f[y][x+1] && f[y][x+1]<f[y][x+2]) return false;
			}
		}
		
		for(int y=0; y<N-2; y++){
			for(int x=0; x<N; x++){
				int n = f[y][x];
				if(y<N-2 && n>f[y+1][x] && f[y+1][x]> f[y+2][x]) return false;
				if(y<N-2 && n<f[y+1][x] && f[y+1][x]< f[y+2][x]) return false;
			}
		}
		
		return true;
	}
	
	static int[][] getCopy(int[][] f){
		int[][] copy = new int[N][N];
		for(int y=0; y<N; y++)
			for(int x=0; x<N; x++)
				copy[y][x] = f[y][x];
		return copy;
	}

}

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