제출 #681706

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
681706		tvladm2009	Bomb (IZhO17_bomb)	C++14	100 / 100	342 ms	110868 KiB

bomb

#include <bits/stdc++.h>

using ll = long long;

int const nmax = 2500;

std::string s[5 + nmax];
int dp[5 + nmax], dp_left[5 + nmax][5 + nmax], dp_right[5 + nmax][5 + nmax], dp_up[5 + nmax][5 + nmax], dp_down[5 + nmax][5 + nmax];

int main() {
  std::ios_base::sync_with_stdio(0);
  std::cin.tie(0);

  int n, m;
  std::cin >> n >> m;
  for(int i = 1;i <= n; i++) {
    std::cin >> s[i];
    s[i] = "#" + s[i];
  }
  for(int i = 1;i <= n; i++)
    for(int j = 1;j <= m; j++) {
      if(s[i][j] == '1') {
        dp_left[i][j] = dp_left[i][j - 1] + 1;
        dp_up[i][j] = dp_up[i - 1][j] + 1;
      }
    }
  for(int i = n; 1 <= i; i--)
    for(int j = m; 1 <= j; j--) {
      if(s[i][j] == '1') {
        dp_right[i][j] = dp_right[i][j + 1] + 1;
        dp_down[i][j] = dp_down[i + 1][j] + 1;
      }
    }
  for(int i = 1;i <= n; i++)
    dp[i] = m + 1;

  int h = n;
  for(int i = 1;i <= n; i++)
    for(int j = 1;j <= m; j++)
      if(s[i][j] == '1') {
        h = std::min(h, dp_up[i][j] + dp_down[i][j] - 1);
        dp[1] = std::min(dp[1], dp_left[i][j] + dp_right[i][j] - 1);
      }
  for(int j = 1;j <= m; j++) {
    int cnt = 0, left = 0, right = m + 1;
    for(int i = 1;i <= n; i++) {
      if(s[i][j] == '1') {
        left = std::max(left, j - dp_left[i][j] + 1);
        right = std::min(right, j + dp_right[i][j] - 1);
        cnt++;
        dp[cnt] = std::min(dp[cnt], right - left + 1);
      } else {
        cnt = 0;
        left = 0;
        right = m + 1;
      }
    }
  }
  for(int j = 1; j <= m; j++) {
    int cnt = 0, left = 0, right = m + 1;
    for(int i = n; 1 <= i; i--) {
      if(s[i][j] == '1') {
        left = std::max(left, j - dp_left[i][j] + 1);
        right = std::min(right, j + dp_right[i][j] - 1);
        cnt++;
        dp[cnt] = std::min(dp[cnt], right - left + 1);
      } else {
        cnt = 0;
        left = 0;
        right = m + 1;
      }
    }
  }
  int result = 0;
  for(int i = 1;i <= h; i++) {
    if(i > 1)
      dp[i] = std::min(dp[i], dp[i - 1]);
    result = std::max(result, dp[i] * i);
  }
  std::cout << result << "\n";
  return 0;
}

• Subtask 1: 100 / 100