qui赞求求~！！！！！！！！！！！！！
2026-03-12 16:41:12
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#include <bits/stdc++.h>
using namespace std;#define Int register int
#define MAXX 20000005
#define mod 998244353
#define Gi 332748118
#define MAXN 800005
#define G 3int quick_pow (int a,int b,int c){
int res = 1;
while (b){
if (b & 1) res = 1ll * res * a % c;
a = 1ll * a * a % c;
b >>= 1;
}
return res;
}int l,limit,r[MAXN];
void NTT (int *a,int type){
for (Int i = 0;i < limit;++ i)
if (i < r[i]) swap (a[i],a[r[i]]);
for (Int mid = 1;mid < limit;mid <<= 1){
int Wn = quick_pow (type == 1 ? G : Gi,(mod - 1) / (mid << 1),mod);
for (Int R = mid << 1,j = 0;j < limit;j += R){
int w = 1;
for (Int k = 0;k < mid;++ k,w = 1ll * w * Wn % mod){
int x = a[j + k],y = 1ll * w * a[j + k + mid] % mod;
a[j + k] = (x + y) % mod,a[j + k + mid] = (x + mod - y) % mod;
}
}
}
if (type == 1) return ;
int Inv = quick_pow (limit,mod - 2,mod);
for (Int i = 0;i < limit;++ i) a[i] = 1ll * a[i] * Inv % mod;
}template <typename T> inline void read (T &t){t = 0;char c = getchar();int f = 1;while (c < '0' || c > '9'){if (c == '-') f = -f;c = getchar();}while (c >= '0' && c <= '9'){t = (t << 3) + (t << 1) + c - '0';c = getchar();} t *= f;}
template <typename T,typename ... Args> inline void read (T &t,Args&... args){read (t);read (args...);}
template <typename T> inline void write (T x){if (x < 0){x = -x;putchar ('-');}if (x > 9) write (x / 10);putchar (x % 10 + '0');}int N,M,S,L;
int A[MAXN],B[MAXN];int inv[MAXX],fac[MAXX];
void SiteLin (int n){
for (Int i = 0;i <= n;++ i){
A[i] = (i & 1) ? mod - inv[i] : inv[i];
B[i] = 1ll * quick_pow (i,n,mod) * inv[i] % mod;
}
limit = 1,l = 0;
while (limit <= (n << 1)) limit <<= 1,l ;
for (Int i = 0;i < limit; i) r[i] = (r[i >> 1] >> 1) | ((i & 1) << l - 1);
NTT (A,1),NTT (B,1);
for (Int i = 0;i < limit;++ i) A[i] = 1ll * A[i] * B[i] % mod;
NTT (A,-1);
}int C (int n,int m){
return 1ll * fac[n] * inv[m] % mod * inv[n - m] % mod;
}signed main(){
read (N,M,S,L);
inv[0] = inv[1] = fac[04天前 来自 浙江
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