Submission #1628554

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Source Code Expand

import java.util.*;

public class Main {
    private static int H;
    private static int W;
    private static int C[][];

    public static void input(){
        Scanner scan = new Scanner(System.in);

        H = scan.nextInt();
        W = scan.nextInt();
        C = new int[H][W];

        for (int i=0;i<H;i++){
            for (int j=0;j<W;j++){
                int x = scan.nextInt();
                if ((i + j) % 2 == 0) C[i][j] = x;
                else C[i][j] = -x;
            }
        }

    }

    public static void main(String args[]) {
        //入力
        input();

        // 累積和
        for (int i = 1; i < H; i++) {
            for (int j = 0; j < W; j++) {
                C[i][j] += C[i - 1][j];
            }
        }
        for (int i = 0; i < H; i++) {
            for (int j = 1; j < W; j++) {
                C[i][j] += C[i][j - 1];
            }
        }

        int ans = 0;
        for (int i = 0; i < H; i++) {
            for (int j = i; j < H; j++) {
                for (int k = 0; k < W; k++) {
                    for (int l = k; l < W; l++) {
                        int tmp = C[j][l];  // 右下
                        if (i > 0) tmp -= C[i - 1][l];  // 右上の一つ上
                        if (k > 0) tmp -= C[j][k - 1];  // 左下の一つ右
                        if (i > 0 && k > 0) tmp += C[i - 1][k - 1];  // 左上の斜め左上(2回ひいた分を足す)
                        if (tmp == 0) ans = Math.max(ans, (j - i + 1) * (l - k + 1));
                    }
                }
            }
        }
        System.out.println(ans);
    }
}

Submission Info

Judge Result