백준 2630 자바 및 C++

풀기 전:

4개의 분할로 계속 나누어서 하나의 덩어리가 될때까지 쪼개는 것을 반복하면 될 것같다.

그것을 바탕으로 문제를 풀어 보겠다.

자바(JAVA)

import java.io.*;
import java.lang.reflect.Array;
import java.util.*;
import java.util.Collections;
public class Main{
    static int arr[][];
    static int BlueCount;
    static int WhiteCount;
    public static boolean isAllSame(int startPosX,int startPosY,int n){
        int firstNum=arr[startPosX][startPosY];
        boolean Same=true;
        for(int i=startPosX;i<startPosX+n;i++){
            for(int j=startPosY;j<startPosY+n;j++){
                if(firstNum!=arr[i][j]){
                    Same=false;
                    break;
                }
            }
        }
        return Same;
    }
    public static void DivideBlue(int startPosX,int startPosY,int n){
        if(n==1){
            if(arr[startPosX][startPosY]==1){
                BlueCount++;
            }
            else {
                WhiteCount++;
            }
            return;
        }
        else if(isAllSame(startPosX,startPosY,n)){
            if(arr[startPosX][startPosY]==1) {
                BlueCount++;
            }
            else{
                WhiteCount++;
            }
            return;
        }
        else{
             DivideBlue(startPosX,startPosY,n/2);
             DivideBlue(startPosX+n/2,startPosY,n/2);
             DivideBlue(startPosX,startPosY+n/2,n/2);
             DivideBlue(startPosX+n/2,startPosY+n/2,n/2);
        }
    }

    public static void main(String[] args) throws IOException {
        Scanner scanner=new Scanner(System.in);
        int n=scanner.nextInt();
        arr=new int[n][n];
        for(int i=0;i<n;i++){
            for(int j=0;j<n;j++){
                arr[i][j]=scanner.nextInt();
            }
        }
        DivideBlue(0,0,n);
        System.out.println(WhiteCount);
        System.out.println(BlueCount);
    }
    }

C++

#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
#include <string>
using namespace std;
int** arr;
int BlueCount = 0;
int WhiteCount = 0;
bool isAllSame(int startPosX, int startPosY, int n) {
	int firstNum = arr[startPosX][startPosY];
	bool Same = true;
	for (int i = startPosX; i < startPosX + n; i++) {
		for (int j = startPosY; j < startPosY + n; j++) {
			if (firstNum != arr[i][j]) {
				Same = false;
				break;
			}
		}
	}
	return Same;
}
void DivideBlue(int startPosX, int startPosY, int n) {
    if (n == 1) {
        if (arr[startPosX][startPosY] == 1) {
            BlueCount++;
        }
        else {
            WhiteCount++;
        }
        return;
    }
    else if (isAllSame(startPosX, startPosY, n)) {
        if (arr[startPosX][startPosY] == 1) {
            BlueCount++;
        }
        else {
            WhiteCount++;
        }
        return;
    }
    else {
        DivideBlue(startPosX, startPosY, n / 2);
        DivideBlue(startPosX + n / 2, startPosY, n / 2);
        DivideBlue(startPosX, startPosY + n / 2, n / 2);
        DivideBlue(startPosX + n / 2, startPosY + n / 2, n / 2);
    }
}
int main(void) {
    int n;
    cin >> n;
    arr = new int* [n];
    for (int i = 0; i < n; i++) {
        arr[i] = new int[n];
    }
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            cin >> arr[i][j];
        }
    }
    DivideBlue(0, 0, n);
    cout << WhiteCount << '\n' << BlueCount;
	
}

6개월후에 다시 풀었을 때:
일단 의식의 흐름대로 풀었다. 위처럼 이쁜 형식으로 풀 수 있었는데 의식의 흐름으로 풀다가 바꾸려했지만 그냥 얼마 안걸릴것같아서 밀고 나갔다.
하지만 다음부터는 위처럼 이쁘게 풀어야 한다. 코드가길어지면 실수할 여지가 매우 많아 지기 때문이다.

import java.io.*;
import java.lang.reflect.Array;
import java.nio.Buffer;
import java.util.*;

public class Main {
    static int white=0;
    static int blue=0;
    static int arr[][];
    public static void divide(int n,int first,int second){
        boolean needDivide=false;
        int firstThing=arr[first][second];
        for(int i=first;i<first+n;i++){
            for(int j=second;j<second+n;j++){
                if(firstThing!=arr[i][j]){
                    needDivide=true;
                }
            }
        }
        if(!needDivide){
            if(firstThing==0){
                white++;
            }
            else{
                blue++;
            }
        }
        else {
            int tmp = arr[first][second];
            boolean firstNeedMore = false;
            for (int i = first; i < first + (n / 2); i++) {
                for (int j = second; j < second + (n / 2); j++) {
                    if (tmp != arr[i][j]) {
                        firstNeedMore = true;
                    }

                }
            }
            if (firstNeedMore) {
                divide(n / 2, first, second);
            } else {
                if (tmp == 0) {
                    white++;
                } else {
                    blue++;
                }
            }
            tmp = arr[first][second + (n / 2)];
            boolean secondNeedMore = false;
            for (int i = first; i < first + (n / 2); i++) {
                for (int j = second + (n / 2); j < second+n; j++) {
                    if (tmp != arr[i][j]) {
                        secondNeedMore = true;
                    }

                }
            }
            if (secondNeedMore) {
                divide(n / 2, first, second + (n / 2));
            } else {
                if (tmp == 0) {
                    white++;
                } else {
                    blue++;
                }
            }
            tmp = arr[first + (n / 2)][second];
            boolean thirdNeedMore = false;
            for (int i = first + (n / 2); i < first+n; i++) {
                for (int j = second; j < second + (n / 2); j++) {
                    if (tmp != arr[i][j]) {
                        thirdNeedMore = true;
                    }

                }
            }
            if (thirdNeedMore) {
                divide(n / 2, first + (n / 2), second);
            } else {
                if (tmp == 0) {
                    white++;
                } else {
                    blue++;
                }
            }
            tmp = arr[first + (n / 2)][second + (n / 2)];
            boolean fourthNeedMore = false;
            for (int i = first + (n / 2); i <first+ n; i++) {
                for (int j = second + (n / 2); j <second+ n; j++) {
                    if (tmp != arr[i][j]) {
                        fourthNeedMore = true;
                    }

                }
            }
            if (fourthNeedMore) {
                divide(n / 2, first + (n / 2), second + (n / 2));
            } else {
                if (tmp == 0) {
                    white++;
                } else {
                    blue++;
                }
            }
        }
    }
    public static void main(String[] args) throws IOException {
       Scanner scanner=new Scanner(System.in);
       int n=scanner.nextInt();
       arr=new int[n+1][n+1];
       for(int i=1;i<=n;i++){
           for(int j=1;j<=n;j++){
               arr[i][j]= scanner.nextInt();
           }
       }
       divide(n,1,1);
        System.out.println(white);
        System.out.println(blue);


    }
}