boj_2580_스도쿠

Author: kimhynsoo

Gold/boj_2580_스도쿠.java

@@ -0,0 +1,89 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+import java.util.StringTokenizer;
+
+public class boj_2580_스도쿠 {
+	
+	static int[][] arr = new int[9][9];
+	
+	public static void main(String[] args) throws IOException {
+		
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		
+		for(int i = 0 ; i < 9 ; i++) {
+		StringTokenizer str = new StringTokenizer(br.readLine());
+		for(int j = 0 ; str.hasMoreTokens();j++) {
+			arr[i][j]= Integer.parseInt(str.nextToken());
+		}
+		}
+
+		dfs(0,0);
+}
+	static void dfs(int row, int col) {
+		
+		if(col == 9) {
+			dfs(row+1,0);
+			return;
+		}
+		
+		if(row == 9) {
+			StringBuilder sb = new StringBuilder();
+			for (int i = 0; i < 9; i++) {
+				for (int j = 0; j < 9; j++) {
+					sb.append(arr[i][j]).append(' ');
+				}
+				sb.append('\n');
+			}
+			System.out.println(sb);
+			
+			System.exit(0);
+		}
+		
+		if(arr[row][col]==0) {
+			for(int i = 1 ; i <= 9 ; i++) {
+				if(check(row, col, i)) {
+					arr[row][col] = i;
+					dfs(row, col+1);
+				}
+			}
+			arr[row][col]=0;
+			return;
+		}
+		
+		dfs(row, col+1);
+	}
+	
+	static boolean check(int row, int col, int value) {
+		
+		//같은열에 무슨 숫자가 비었는지
+		for(int i = 0 ; i < 9 ; i ++) {
+			if(arr[row][i] == value) {
+				return false;
+			}
+		}
+		
+		//같은행에 무슨 숫자가 비었는지
+		for(int i = 0 ; i < 9 ; i ++) {
+			if(arr[i][col] == value) {
+				return false;
+			}
+		}
+		
+		//같은 네모에 뭐가 있는지
+		int ind_row = (row/3)*3;
+		int ind_col = (col/3)*3;
+		
+		for(int i = ind_row ; i < ind_row+3 ; i ++) {
+			for(int j = ind_col ; j < ind_col +3 ; j++) {
+				if(arr[i][j] == value)
+					return false;
+			}
+		}
+		
+		return true;
+	}
+	
+
+}