[BOJ/JAVA] 백준 1285번 : 동전 뒤집기

1285번: 동전 뒤집기

 

 

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• 풀이

 

열만 backtracking하면서 메소드를 돌려주고 메소드 안에서 행도 돌려주면서 T의 최소 개수를 찾아준다.

 

 

 

• 코드

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.List;
import java.util.PriorityQueue;

public class Main {
	static int N, answer;
	static char[][] array;

	public static void main(String[] args) throws Exception {
		SetData();
		System.out.println(answer);
	}

	// 데이터
	private static void SetData() throws Exception {
		InputReader in = new InputReader(System.in);

		N = in.nextInt();
		answer = Integer.MAX_VALUE;
		array = new char[N][N];
		
        for(int i = 0; i < N ; i ++){
            array[i] = in.nextLine().toCharArray();
        }
		
        solve(0);
	}
	
    public static void solve(int row){
        if(row == N){
            int count = 0;
            for(char[] i : array){
                int temp = 0;
                for(char j : i){
                    if(j == 'T'){
                        temp ++;
                    }
                }
                count = count + Math.min(temp,N-temp);
            }
            answer = Math.min(count,answer);
            return;
        }
        solve(row+1);
        for(int i = 0 ; i < N; i ++){
            array[i][row] = array[i][row] == 'H'?'T':'H';
        }
        solve(row+1);
    }
}

class Delivery implements Comparable<Delivery> {
	int from;
	int to;
	int weight;

	public Delivery(int from, int to, int weight) {
		this.from = from;
		this.to = to;
		this.weight = weight;
	}

	@Override
	public int compareTo(Delivery o) {
		if (this.to < o.to) {
			return -1;
		} else if (this.to == o.to) {
			if (this.from < o.from) {
				return -1;
			}
		}
		return 1;
	}
}

class InputReader {
	private final InputStream stream;
	private final byte[] buf = new byte[8192];
	private int curChar, snumChars;

	public InputReader(InputStream st) {
		this.stream = st;
	}

	public int read() {
		if (snumChars == -1)
			throw new InputMismatchException();
		if (curChar >= snumChars) {
			curChar = 0;
			try {
				snumChars = stream.read(buf);
			} catch (IOException e) {
				throw new InputMismatchException();
			}
			if (snumChars <= 0)
				return -1;
		}
		return buf[curChar++];
	}

	public int nextInt() {
		int c = read();
		while (isSpaceChar(c)) {
			c = read();
		}
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		int res = 0;
		do {
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	public long nextLong() {
		int c = read();
		while (isSpaceChar(c)) {
			c = read();
		}
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		long res = 0;
		do {
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	public int[] nextIntArray(int n) {
		int a[] = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = nextInt();
		}
		return a;
	}

	public String nextLine() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do {
			res.appendCodePoint(c);
			c = read();
		} while (!isEndOfLine(c));
		return res.toString();
	}

	public boolean isSpaceChar(int c) {
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}

	private boolean isEndOfLine(int c) {
		return c == '\n' || c == '\r' || c == -1;
	}
}