Submission #346448

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
346448	2021-01-09T18:46:20 Z	CaroLinda	Tents (JOI18_tents)	C++14	100 / 100	135 ms	71020 KB

tents

#include <bits/stdc++.h>

#define ll long long

const int MAX = 3010 ;
const ll MOD = 1e9+7 ;

using namespace std ;

int N , M ;
ll dp[MAX][MAX] ;

int main()
{
	scanf("%d %d", &N, &M ) ;

	for(int i = 0 ; i <= max(N,M) ; i++ ) dp[0][i] = dp[i][0] = 1 ;

	for(int i= 1 ; i <= N ; i++ )
	{
		ll bin = (ll)i * (i-1)  ;
		bin = (bin>>1LL ) % MOD ;

		ll c = (4*i) % MOD ;

		for(int j = 1 , aux = 0 ; j <= M ; j++, aux += i )
		{
			if( aux >= MOD ) aux -= MOD ;

			ll &ptr = dp[i][j] ;

			ptr = dp[i][j-1] ;
			ptr += ( c * dp[i-1][j-1] ) % MOD ;

			if( ptr >= MOD ) ptr -= MOD ;

			if(i >= 2 )
			{
				ptr += ( bin * dp[i-2][j-1] ) % MOD ;
				if( ptr >= MOD ) ptr -= MOD ;
			}

			if( j >= 2 )
			{
				ptr += ( aux * dp[i-1][j-2] ) % MOD ;
				if( ptr >= MOD ) ptr -= MOD ;
			}

		}

	}


	ll ans = dp[N][M] - 1LL ;

	if( ans < 0 ) ans += MOD ;

	printf("%lld\n", ans ) ;

}

Compilation message

tents.cpp: In function 'int main()':
tents.cpp:15:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   15 |  scanf("%d %d", &N, &M ) ;
      |  ~~~~~^~~~~~~~~~~~~~~~~~

Subtask #1

48.0 / 48.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	1 ms	364 KB	Output is correct
2	Correct	1 ms	1004 KB	Output is correct
3	Correct	1 ms	492 KB	Output is correct
4	Correct	1 ms	1132 KB	Output is correct
5	Correct	1 ms	1536 KB	Output is correct
6	Correct	1 ms	1388 KB	Output is correct
7	Correct	1 ms	1388 KB	Output is correct
8	Correct	1 ms	1516 KB	Output is correct
9	Correct	1 ms	876 KB	Output is correct
10	Correct	2 ms	1792 KB	Output is correct
11	Correct	1 ms	1516 KB	Output is correct
12	Correct	2 ms	2176 KB	Output is correct

Subtask #2

52.0 / 52.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	1 ms	364 KB	Output is correct
2	Correct	1 ms	1004 KB	Output is correct
3	Correct	1 ms	492 KB	Output is correct
4	Correct	1 ms	1132 KB	Output is correct
5	Correct	1 ms	1536 KB	Output is correct
6	Correct	1 ms	1388 KB	Output is correct
7	Correct	1 ms	1388 KB	Output is correct
8	Correct	1 ms	1516 KB	Output is correct
9	Correct	1 ms	876 KB	Output is correct
10	Correct	2 ms	1792 KB	Output is correct
11	Correct	1 ms	1516 KB	Output is correct
12	Correct	2 ms	2176 KB	Output is correct
13	Correct	4 ms	7788 KB	Output is correct
14	Correct	6 ms	9708 KB	Output is correct
15	Correct	91 ms	55276 KB	Output is correct
16	Correct	9 ms	9452 KB	Output is correct
17	Correct	23 ms	17388 KB	Output is correct
18	Correct	26 ms	17920 KB	Output is correct
19	Correct	102 ms	62956 KB	Output is correct
20	Correct	82 ms	50924 KB	Output is correct
21	Correct	56 ms	35564 KB	Output is correct
22	Correct	57 ms	35584 KB	Output is correct
23	Correct	38 ms	27116 KB	Output is correct
24	Correct	135 ms	71020 KB	Output is correct
25	Correct	103 ms	61420 KB	Output is correct
26	Correct	117 ms	66796 KB	Output is correct
27	Correct	130 ms	69356 KB	Output is correct