Submission #60588770

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Source Code Expand

#pragma GCC optimize ("Ofast")
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i=(a); i<(b); i++)
#define FORD(i, a, b) for (int i=(a); i>(b); i--)
#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(), (x).end()
#define PPC(x) __builtin_popcountll(x)
#define MSB(x) (63 - __builtin_clzll(x))
#define LSB(x) __builtin_ctz(x)
#define ARG(x, i) (get<i>(x))
#define LAST(x) std::prev(x.end())
#define ithBit(m, i) ((m) >> (i) & 1)
#define pb push_back
#define ft first
#define sd second
#define kw(a) ((a) * (a))
#define VLD(i, j) (0 <= (i) and (i) < n and 0 <= (j) and (j) < m)
#ifdef DEBUG
#include "debug.h"
#else
#define dbg(...) 0
#endif
	
using namespace std; 
template <typename T1, typename T2> inline void remin(T1& a, T2 b) { a = min(a, (T1)b);	}
template <typename T1, typename T2> inline void remax(T1& a, T2 b) { a = max(a, (T1)b);	}

const int maxN = 1 << 18, mod = 998244353;

template <typename T1, typename T2> inline void addMod(T1& a, T2 b) { a = (a + b) % mod; }
template <typename T1, typename T2> inline void multMod(T1& a, T2 b) { a = a * b % mod; }

long long qpow(long long a, long long b)
{
	long long ret = 1ll;
	for (; b != 0; b /= 2)
	{
		if (b & 1)	multMod(ret, a);
		multMod(a, a);
	}
	return ret;
}

template <typename T1, typename T2> inline void subMod(T1& a, T2 b) { a = (a - b%mod + mod) % mod; }
template <typename T1, typename T2> inline void divMod(T1& a, T2 b) { a = a * qpow(b, mod-2) % mod; }

long long fact[maxN], tcaf[maxN];
long long dp[maxN];
int T[maxN];

void calcDp(int n)
{
	dp[1] = 1;
	FOR(i, 2, n+1)
	{
		if (i % 2 == 0)
			dp[i] = 0;
		else
			dp[i] = dp[i-2] * (i-2) % mod;
	}
	
	fact[0] = tcaf[0] = 1ll;
	FOR(i, 1, maxN)
		fact[i] = fact[i-1] * i % mod;
	tcaf[maxN-1] = qpow(fact[maxN-1], mod-2);
	FORD(i, maxN-1, 0)
		tcaf[i-1] = tcaf[i] * i % mod;
}

void solve()
{
	int n, start = 0, sum = 0;
	scanf ("%d", &n);
	long long res = 1;
	T[0] = -1;

	calcDp(n);

	FOR(i, 1, n+1)
	{
		scanf ("%d", T+i);
		if (T[i] == T[i-1])
			continue;

		int x = (i - start) / 2;
		sum += x;
		multMod(res, tcaf[x]);
		multMod(res, dp[i - start]);
		start = i;
	}
	
	int x = (n+1 - start) / 2;
	sum += x;
	multMod(res, tcaf[x]);
	multMod(res, dp[n+1 - start]);
	multMod(res, fact[sum]);

	if (T[1] == 0)
		res = 0;
		
	printf("%lld\n", res);
}

int main()
{
	int t = 1;
//	scanf ("%d", &t);
	FOR(tid, 1, t+1)
	{
//		printf("Case #%d: ", tid);
		solve();
	}
	return 0;
}

Submission Info

Compile Error

Main.cpp: In function ‘void solve()’:
Main.cpp:74:15: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   74 |         scanf ("%d", &n);
      |         ~~~~~~^~~~~~~~~~
Main.cpp:82:23: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   82 |                 scanf ("%d", T+i);
      |                 ~~~~~~^~~~~~~~~~~

Judge Result