Submission #2375756

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Source Code Expand

#include <bits/stdc++.h>
#define pq priority_queue
using namespace std;
constexpr long long gcd(long long a, long long b){return b ? gcd(b, a % b) : a;}
constexpr long long lcm(long long a, long long b){return a / gcd(a, b) * b;}
constexpr int INF = 1e9, MOD = INF + 7, around[] = {0, 1, 1, -1, -1, 0, -1, 1, 0, 0};
constexpr int mod_pow(long long x, long long n, const int mod){long long ret=1;while(n){if(n&1)(ret*=x)%=mod;(x*=x)%=mod;n>>=1;}return ret;}
template<int n> struct Prime{bool arr[n+1];constexpr bool operator[](int k){return arr[k];}constexpr Prime():arr(){for(int i=2;i<n;i++){arr[i]=true;for(int j=2;j*j<=i;j++){if(!(i%j))arr[i]=false;}}}};
template<int n> struct Factorial{long long arr[n+1],ary[n+1];constexpr Factorial():arr(),ary(){arr[0]=1;ary[0]=1;for(int i=0;i<n;i++){arr[i+1]=arr[i]*(i+1)%MOD;ary[i+1]=mod_pow(arr[i+1],MOD-2,MOD);}}};
constexpr Factorial<1010> fact; constexpr Prime<10> prime;
constexpr long long comb(int a, int b){if(a < b) return 0LL;if(!a or !b) return 1LL; long long pos = fact.arr[a], pot = fact.ary[a - b], por = fact.ary[b]; return pos * pot % MOD * por % MOD;}
template<int n> struct Bernoulli{long long arr[n+1];constexpr Bernoulli():arr(){arr[0]=1;for(int i=1;i<=n;i++){long long sum=0;for(int j=0;j<i;j++){(sum+=comb(i+1,j)*arr[j]%MOD)%=MOD;}arr[i]=(MOD-mod_pow(i+1,MOD-2,MOD))%MOD*sum%MOD;}}};
constexpr int vx[] = {1, 0, -1, 0}, vy[] = {0, 1, 0, -1};
constexpr long double PI = abs(acos(-1));
constexpr int sqrtN = 512, logN = 32;
constexpr long long LINF=1e18;

int s[110][110], t[110][110];

int main(){
	int h, w; cin >> h >> w;
	for(int i = 0; i < h; i++){
		for(int j = 0; j < w; j++){
			int a; cin >> a;
			
			if((i + j) % 2) s[i + 1][j + 1] = a;
			else t[i + 1][j + 1] = a;
		}
	}
	
	for(int i = 1; i <= h; i++) for(int j = 1; j <= w; j++) s[i][j] += s[i - 1][j] + s[i][j - 1] - s[i - 1][j - 1];
	for(int i = 1; i <= h; i++) for(int j = 1; j <= w; j++) t[i][j] += t[i - 1][j] + t[i][j - 1] - t[i - 1][j - 1];
	
	int ma = 0;
	for(int i = 1; i <= h; i++){
		for(int j = 1; j <= w; j++){
			for(int k = i; k <= h; k++){
				for(int l = j; l <= w; l++){
					int A = s[k][l] - s[k][j - 1] - s[i - 1][l] + s[i - 1][j - 1];
					int B = t[k][l] - t[k][j - 1] - t[i - 1][l] + t[i - 1][j - 1];
						
					if(A == B) ma = max(ma, (abs(k - i) + 1) * (abs(l - j) + 1));
				}
			}
		}
	}
	
	cout << ma << endl;
	return 0;
}

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