Submission #20170

# Submission time Handle Problem Language Result Execution time Memory
20170 2016-03-01T05:48:21 Z sui 괄호 (kriii4_R) C++14
8 / 100
122 ms 48604 KB
#define _CRT_SECURE_NO_WARNINGS // scanf(), gets() (needed for Visual C++)

//#define NDEBUG
#include <cassert>

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <functional>
#include <string>
#include <vector>

#include <queue>
#include <set>
#include <map>
#include <unordered_map>
#include <stack>
#include <deque>


using namespace std;

#define MEMSET(x, WITH) memset(x, (WITH), sizeof(x))
#define FOR(i, E) for(int i=0; i<(E); i++)
#define REP(i, LO, HI) for(int i=(LO); i<=(HI); i++)

#define GETINT(x) scanf("%d", &x)
#define GETDBL(x) scanf("%lf", &x)
#define GETSTR(x) scanf("%s", x)
#define NEWINT(x) int x; scanf("%d", &x)
#define NEWDBL(x) double x; scanf("%lf", &x)
#define NEWLN putchar('\n')

typedef long long ll;

const ll MOD = 1000000007;
//const double PI = atan(1) * 4;

#ifdef _WIN32
#define popcnt __popcnt
#else
#define popcnt __builtin_popcount
#endif





const int SZ = 2000333;

ll inv[SZ];
ll fac[SZ];
ll invfac[SZ];

void precalc() {
	inv[1] = 1;
	for (int x=2; x<SZ; x++) {
		ll q = MOD / x;
		ll r = MOD % x;

		q = MOD - q;
		inv[x] = q * inv[r] % MOD;
	}

	fac[0] = 1;
	for (int x=1; x<SZ; x++) fac[x] = fac[x-1] * x % MOD;

	invfac[0] = 1;
	for (int x=1; x<SZ; x++) invfac[x] = invfac[x-1] * inv[x] % MOD;
}



int N, K;


int main() {
	precalc();


	cin >> N >> K;



	ll sum = 1;
	ll a = 1;

	for (int i=2; i<=N; i++) {
		if (i&1) {
			sum = (sum + sum - a + MOD) % MOD;
			int n = i/2 + 1;
			a = fac[2*n] * invfac[n] % MOD * invfac[n+1] % MOD;
		} 
		else {
			
			sum = (sum + sum) % MOD;
		}
	}


	cout << sum << endl;


	return 0;
}
# Verdict Execution time Memory Grader output
1 Correct 116 ms 48604 KB Output is correct
2 Correct 106 ms 48604 KB Output is correct
3 Correct 106 ms 48604 KB Output is correct
4 Correct 113 ms 48604 KB Output is correct
5 Correct 122 ms 48604 KB Output is correct
6 Correct 106 ms 48604 KB Output is correct
7 Correct 120 ms 48604 KB Output is correct
8 Correct 111 ms 48604 KB Output is correct
9 Correct 107 ms 48604 KB Output is correct
10 Correct 100 ms 48604 KB Output is correct
11 Correct 109 ms 48604 KB Output is correct
12 Correct 116 ms 48604 KB Output is correct
13 Correct 110 ms 48604 KB Output is correct
14 Correct 107 ms 48604 KB Output is correct
15 Correct 117 ms 48604 KB Output is correct
16 Correct 107 ms 48604 KB Output is correct
17 Correct 118 ms 48604 KB Output is correct
18 Correct 118 ms 48604 KB Output is correct
19 Correct 120 ms 48604 KB Output is correct
20 Correct 119 ms 48604 KB Output is correct
# Verdict Execution time Memory Grader output
1 Incorrect 118 ms 48604 KB Output isn't correct
2 Halted 0 ms 0 KB -