# Winning Tetris (tetris) 20/100

**URL:** <https://forum.olinfo.it/t/winning-tetris-tetris-20-100/8553>\
**Category:** Aiuto\
**Created:** [20 Ottobre 2023, 8:54pm UTC](https://forum.olinfo.it/t/winning-tetris-tetris-20-100/8553 "2023-10-20T20:54:19Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![seqq](https://forum.olinfo.it/letter_avatar_proxy/v4/letter/s/278dde/32.png) [@seqq](https://forum.olinfo.it/u/seqq)\
**Post date:** [20 Ottobre 2023, 8:54pm UTC](https://forum.olinfo.it/t/winning-tetris-tetris-20-100/8553/1 "2023-10-20T20:54:19Z")

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Buonasera, stavo cercando di risolvere il problema “tetris”, ma non riesco a superare 4 testcase (12, 13, 20, 24).  
Questo è il codice:

```auto
#include <bits/stdc++.h>
using namespace std;

int main(){   
	int N, M;
		// H W

	ifstream cin("input.txt");
	ofstream cout("output.txt");
	cin >> N >> M;  
	if(N == 2 && M == 2){
		cout << "1\n0 0\n0 0";
		return 0;
	}
	if(N % 4 != 0 && M % 4 != 0){
		cout << -1;
		return 0;
	}

	if(N % 4 == 0) 
	    cout << M * N / 4 << '\n';
	else 
	    cout << N * M / 4 << '\n';
	
	int b = 0;

	for(int i = 0; i < N; ++i){
		if(N % 4 == 0 && M % 4 != 0){
			if(i % 4 == 0) b += M;
		}
			
		for(int j = 0; j < M; ++j){
			if(M % 4 == 0){
				if(j % 4 == 0) ++b;
				cout << b - 1 << " ";
			}
			else if(N % 4 == 0) 
				cout << b + j - M << " ";
		}
		cout << '\n';
	}

	return 0;
}

```

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<div class="post-metadata">

**Author:** ![fve5](https://forum.olinfo.it/user_avatar/forum.olinfo.it/fve5/32/3229_2.png) [@fve5](https://forum.olinfo.it/u/fve5)\
**Post date:** [20 Ottobre 2023, 8:58pm UTC](https://forum.olinfo.it/t/winning-tetris-tetris-20-100/8553/2 "2023-10-20T20:58:12Z")

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Sicuro che se N e M non sono divisibili per 4 allora non c’è soluzione? Cosa succede per l’input `6 6`?

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<div class="post-metadata">

**Author:** ![seqq](https://forum.olinfo.it/letter_avatar_proxy/v4/letter/s/278dde/32.png) [@seqq](https://forum.olinfo.it/u/seqq)\
**Post date:** [21 Ottobre 2023, 9:30am UTC](https://forum.olinfo.it/t/winning-tetris-tetris-20-100/8553/3 "2023-10-21T09:30:22Z")

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Grazie mille, mi è bastato solo l’input per capire l’errore!