畫個方塊詛咒你？

數學畫圖軟件

前綴和建圖

#include<bits/stdc++.h>
#define re register
#define f(i, a, b) for(re int i = a; i <= b; i++)
using namespace std;

int n, m, a[101][101], b[101][101], ans = 1, l = 2;

signed main(){
	scanf("%d%d", &n, &m);
	f(i, 1, n)
		f(j, 1, m){
			scanf("%d", &a[i][j]);
			b[i][j] = b[i - 1][j] + b[i][j - 1] - b[i - 1][j - 1] + a[i][j];//求前綴和
		}
	while(l < min(n, m)){
		f(i, l, n)
			f(j, l, m)
				if(b[i][j] - b[i - l][j] - b[i][j - l] + b[i - l][j - l] == pow(l, 2))//求子矩陣和 
					ans = max(ans, l);
		l++;
	}
	printf("%d\n", ans); 
	return 0;
}

dp建圖

#include<bits/stdc++.h>
#define re register
#define f(i, a, b) for(re int i = a; i <= b; ++i)
using namespace std;

int n, m, a[101][101], f[101][101], ans;

int main(){
	scanf("%d%d", &n, &m);
	f(i, 1, n)
		f(j, 1, m){
			scanf("%d", &a[i][j]);
			if(a[i][j] == 1) f[i][j] = min(f[i - 1][j - 1], min(f[i][j - 1], f[i - 1][j])) + 1;
			ans = max(ans, f[i][j]);
		}
	printf("%d\n", ans);
	return 0;
}

真·數學軟件-腳趾Pro