oj.uz

Submission #62732

# Submission time Handle Problem Language Result Execution time Memory
62732 2018-07-29T23:35:52 Z kingpig9 Tents (JOI18_tents) C++11
48 / 100
 2000 ms 49632 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int MAXN = 3018;
const int MOD = 1e9 + 7;

//#define debug(...) fprintf(stderr, __VA_ARGS__)
#define debug(...)
#define fi first
#define se second
#define all(v) (v).begin(), (v).end()
#define fillchar(a, s) memset((a), (s), sizeof(a))

void addeq (int &x, int y) {
	x += y;
	if (x >= MOD) {
		x -= MOD;
	}
}

int add (int x, int y) {
	addeq(x, y);
	return x;
}

int mult (int x, int y) {
	return ll(x) * y % MOD;
}

int mult (int x, int y, int z) {
	return mult(mult(x, y), z);
}

int mult (int x, int y, int z, int w) {
	return mult(mult(x, y), mult(z, w));
}

int cho[MAXN][MAXN];
int fact[MAXN];
int nterm[MAXN][MAXN];
int pwr4[MAXN];

void precomp() {
	for (int i = 0; i < MAXN; i++) {
		cho[i][0] = 1;
		for (int j = 1; j <= i; j++) {
			cho[i][j] = add(cho[i - 1][j], cho[i - 1][j - 1]);
		}
	}

	fact[0] = 1;
	for (int i = 1; i < MAXN; i++) {
		fact[i] = mult(fact[i - 1], i);
	}

	for (int i = 0; i < MAXN; i++) {
		nterm[i][0] = 1;	//start at i = 0 for the same reason 0 choose 0 is 1.
		for (int j = 1; ; j++) {
			int ntop = i + 2 - 2 * j;
			if (ntop < 2) {
				break;
			}
			nterm[i][j] = mult(nterm[i][j - 1], cho[ntop][2]);
		}
	}

	pwr4[0] = 1;
	for (int i = 1; i < MAXN; i++) {
		pwr4[i] = mult(pwr4[i - 1], 4);
	}
}

int N, M;

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

	int ans = 0;
	for (int h = 0; h <= N; h++) {
		for (int v = 0; v <= M; v++) {
			int tcol = 2 * h + v, trow = 2 * v + h;	//# of cols taken, # of rows taken
			if (tcol > M || trow > N) {
				break;
			}

			debug("h = %d, v = %d\n", h, v);
			int nwayv = mult(cho[M][v], nterm[N][v]);
			debug("nwayv = cho[%d][%d] * nterm[%d][%d] = %d\n", M, v, N, v, nwayv);
			int nwayh = mult(cho[N - 2 * v][h], nterm[M - v][h]);
			debug("nwayh = cho[%d][%d] * nterm[%d][%d] = %d\n", N - 2 * v, h, M - v, h, nwayh);

			//now here comes this one
			int nsing = 0;
			int rrem = N - trow, crem = M - tcol;
			for (int i = 0; i <= rrem && i <= crem; i++) {
				debug("nsing += C(%d, %d) * C(%d, %d) * %d! * 4^%d\n", rrem, i, crem, i, i, i);
				addeq(nsing, mult(cho[rrem][i], cho[crem][i], fact[i], pwr4[i]));
			}
			debug("nsing = %d\n", nsing);

			addeq(ans, mult(nwayv, nwayh, nsing));
		}
	}
	printf("%d\n", add(ans, MOD - 1));
}

Compilation message

tents.cpp: In function 'int main()':
tents.cpp:81:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &N, &M);
  ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
48.0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 76 ms 49236 KB Output is correct
2 Correct 65 ms 49260 KB Output is correct
3 Correct 69 ms 49260 KB Output is correct
4 Correct 83 ms 49340 KB Output is correct
5 Correct 75 ms 49540 KB Output is correct
6 Correct 73 ms 49540 KB Output is correct
7 Correct 74 ms 49540 KB Output is correct
8 Correct 75 ms 49544 KB Output is correct
9 Correct 78 ms 49632 KB Output is correct
10 Correct 71 ms 49632 KB Output is correct
11 Correct 69 ms 49632 KB Output is correct
12 Correct 76 ms 49632 KB Output is correct

Subtask #2
0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 76 ms 49236 KB Output is correct
2 Correct 65 ms 49260 KB Output is correct
3 Correct 69 ms 49260 KB Output is correct
4 Correct 83 ms 49340 KB Output is correct
5 Correct 75 ms 49540 KB Output is correct
6 Correct 73 ms 49540 KB Output is correct
7 Correct 74 ms 49540 KB Output is correct
8 Correct 75 ms 49544 KB Output is correct
9 Correct 78 ms 49632 KB Output is correct
10 Correct 71 ms 49632 KB Output is correct
11 Correct 69 ms 49632 KB Output is correct
12 Correct 76 ms 49632 KB Output is correct
13 Correct 75 ms 49632 KB Output is correct
14 Correct 68 ms 49632 KB Output is correct
15 Execution timed out 2069 ms 49632 KB Time limit exceeded
16 Halted 0 ms 0 KB -