Problem A. Dynamic Grid
Problem
We have a grid with R rows and C columns in which every entry is either 0 or 1. We are going to perform N operations on the grid, each of which is one of the following:
- Operation M: Change a number in one cell of the grid to 0 or 1
- Operation Q: Determine the number of different connected regions of 1s. A connected region of 1s is a subset of cells that are all 1, in which any cell in the region can be reached from any other cell in the region by traveling between cells along edges (not corners).
Input
The first line of the input gives the number of test cases, T. T test cases follow. Each test case starts with one line with two integers, R and C, which represent the number of rows and columns in the grid. Then, there are R lines of C characters each, in which every character is either 0
or 1
. These lines represent the initial state of the grid.
M x y z
, meaning that the cell at row x and column y should be changed to the value z. All operation Qs will be of the form Q
.
Output
For each test case, output one line containing "Case #x:", where x is the test case number (starting from 1). Then, for every operation Q in the test case, in order, output one line containing the number of connected regions of 1s.
Limits
1 ≤ T ≤ 10.
1 ≤ R, C ≤ 100.
0 ≤ x < R.
0 ≤ y < C.
0 ≤ z ≤ 1.
Small dataset
1 ≤ N ≤ 10.
Large dataset
1 ≤ N ≤ 1000.
Sample
Input |
Output |
1 4 4 0101 0010 0100 1111 7 Q M 0 2 1 Q M 2 2 0 Q M 2 1 0 Q |
Case #1: 4 2 2 2 |
import java.io.FileNotFoundException; import java.io.PrintWriter; import java.io.Writer; import java.util.Arrays; import java.util.Scanner; public class Q1 { /* * 1 4 4 0101 0010 0100 1111 7 Q M 0 2 1 Q M 2 2 0 Q M 2 1 0 Q 1 4 4 0101 1010 0101 1111 1 Q */ static int a[][]; static int mark[][]; static void markA(int x, int y){ if(x>=a.length || x<0 || y<0 || y>=a[0].length || a[x][y]==0 ||mark[x][y]==1){ return; } if(a[x][y]==1){ mark[x][y]=1; } //You if(y<a[0].length-1 ){ markA(x, y+1); } //zuo if(y>0){ markA(x, y-1); } //xia if(x<a.length-1){ markA(x+1, y); } if(x>0){ markA(x-1, y); } } static int query(){ int count=0; for(int i=0; i<a.length; i++){ for(int j=0; j<a[0].length; j++){ if(mark[i][j]==0 && a[i][j]==1){ count++; // System.out.println(i +":: "+j); // System.out.println(count); markA(i, j); // System.out.println(Arrays.toString(mark[0])); // System.out.println(Arrays.toString(mark[1])); // System.out.println(Arrays.toString(mark[2])); // System.out.println(Arrays.toString(mark[3])); } } } return count; } public static void main(String[] args) throws FileNotFoundException { // TODO Auto-generated method stub Scanner scanner = new Scanner(System.in); PrintWriter writer = new PrintWriter("out.txt"); int t=scanner.nextInt(); int c,r; int m; //scanner.nextLine(); for(int ttt=0; ttt<t;++ttt){ c=scanner.nextInt(); r=scanner.nextInt(); scanner.nextLine(); a=new int[c][r]; mark= new int[c][r]; for(int i=0; i<c; i++){ String line =scanner.nextLine(); for(int j=0; j<r; j++){ a[i][j]=line.charAt(j)-'0'; } } writer.println("Case #"+(ttt+1)+":"); m=scanner.nextInt(); for(int i=0; i<m;i++){ String x=scanner.next(); int x1,y1,value; if(x.equals("Q")){ writer.println(query()); mark=new int[c][r]; }else if(x.equals("M")){ x1=scanner.nextInt(); y1=scanner.nextInt(); value = scanner.nextInt(); a[x1][y1]=value; mark=new int[c][r]; } } } //int result=query(); //System.out.println(result); scanner.close(); writer.close(); } }