Pizza

#include <iostream>
#include <set>

#define ll long long

using namespace std;

int n,m;
string s[200];
set<char> cset;

ll count(int rnum) {
	ll res = 0;
	for (int i=0;i<=n-rnum;i++) {
		int a=0;int b=0;
		while (b<m) {
			for (int j=0;j<rnum;j++) {
			while (cset.count(s[i+j][b]) && a <=b) {
				for (int k=0;k<rnum;k++) {
					cset.erase(s[i+k][a]);
				}
				res+=b-a;
				a++;
			}
			if (a<=b)
			cset.insert(s[i+j][b]);
			}
			b++;
		}
		while (a<m) {
			res+=b-a; a++;
		}
		cset.clear();
	}
	return res;
}

int main() {
	cin >> n >> m;
	for (int i=0;i<n;i++) cin >> s[i];
	ll res = 0;
	for (int i=1;i<=26;i++) {
		res += count(i);
//		cout << i << " " << res << "\n";
	}
	cout << res << "\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED