Submission #44996307

---

Source Code Expand

#include<bits/stdc++.h>
#define LL long long
#define DB double
#define MOD 998244353
#define ls(x) x << 1
#define rs(x) x << 1 | 1
#define lowbit(x) x & (-x)
#define PII pair<int, int>
#define MP make_pair
#define VI vector<int>
#define VII vector<int>::iterator
#define all(x) x.begin(), x.end()
#define EB emplace_back
#define SI set<int>
#define SII set<int>::iterator
#define QI queue<int>
using namespace std;
template<typename T> void chkmn(T &a, const T &b) { (a > b) && (a = b); }
template<typename T> void chkmx(T &a, const T &b) { (a < b) && (a = b); }
int inc(const int &a, const int &b) { return a + b >= MOD ? a + b - MOD : a + b; }
int dec(const int &a, const int &b) { return a - b < 0 ? a - b + MOD : a - b; }
int mul(const int &a, const int &b) { return 1LL * a * b % MOD; }
int sqr(const int &a) { return 1LL * a * a % MOD; }
void Inc(int &a, const int &b) { ((a += b) >= MOD) && (a -= MOD); }
void Dec(int &a, const int &b) { ((a -= b) < 0) && (a += MOD); }
void Mul(int &a, const int &b) { a = 1LL * a * b % MOD; }
void Sqr(int &a) { a = 1LL * a * a % MOD; }
int qwqmi(int x, int k = MOD - 2)
{
	int res = 1;
	while(k)
	{
		if(k & 1) Mul(res, x);
		Sqr(x), k >>= 1;
	}
	return res;
}
const int N = 1e6 + 5;
const int F = 23;
char ch[N]; 
int n, cnt;
int w[N][F];
int f[N][F], ans;
int main()
{
	scanf("%s", ch + 1);
	n = strlen(ch + 1);
	for(int i = 1; i <= n; ++i)
	{
		if(ch[i] != 'B') w[i][0] = 1;
		cnt += (ch[i] == '?');
	}
	for(int j = 1; j < F; ++j)
		for(int i = 1; i + (1 << j) - 1 <= n; ++i)
			w[i][j] = min(w[i][j - 1], w[i + (1 << (j - 1))][j - 1]);
	f[n + 1][0] = 1;
	for(int i = n; i >= 1; --i)
	{
		if(ch[i] != 'B')
		{
			for(int j = 0; j < F; ++j)
				f[i][j] = f[i + 1][j];
		}
		if(ch[i] != 'S')
		{
			Inc(f[i][1], f[i + 1][0]);
			for(int j = 2; j < F; ++j)
				if(w[i + 1][j - 2])
					Inc(f[i][j], f[i + (1 << (j - 2)) + 1][j - 1]);
		}
	}
	for(int j = 0; j < F; ++j)
		Inc(ans, f[1][j]);
	ans = dec(qwqmi(2, cnt), ans);
	printf("%d\n", ans);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:46:7: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   46 |  scanf("%s", ch + 1);
      |  ~~~~~^~~~~~~~~~~~~~

Judge Result