HDU5829 NTT

以下这份代码并没有过。但感觉没有问题。不是蜜汁WA就是蜜汁T。

#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
typedef long long ll;
using namespace std;
const int mod = 998244353;
const int N = 262144, K = 17;
int i;
int P = 998244353, G = 3, g[K+1], ng[K+10], inv[N+10];
ll A[N*2+10], B[N*2+10];
ll pow(ll a, int n){
    ll ans = 1;
    while(n){
        if(n&1)
            ans = ans*a%P;
        a = a*a%P;
        n >>= 1;
    }
    return ans;
}
void NTT(ll*a,int n,int t){
    for(int i=1,j=0;i<n-1;i++){
        for(int s=n;j^=s>>=1,~j&s;);
        if(i<j)swap(a[i], a[j]);
    }
    for(int d=0;(1<<d)<n;d++){
        int m=1<<d,m2=m<<1;
        ll _w=pow(G, (P-1)>>(d+1));
        if(t != 1) _w = pow(_w, P-2);
        for(int i=0;i<n;i+=m2)for(ll w=1,j=0;j<m;j++){
            ll&A=a[i+j+m],&B=a[i+j],t=w*A%P;
            A=B-t;if(A<0)A+=P;
            B=B+t;if(B>=P)B-=P;
            w=w*_w%P;//////////////////////
        }
    }
    if(t==-1)for(int i=0,j=pow(n, P-2);i<n;i++)a[i]=a[i]*j%P;
}

/*****************另一份NTT模板
void change (ll y[], int len) {
    for(int i = 1, j = len / 2; i < len - 1; i++) {
        if(i < j) swap(y[i], y[j]);
        int k = len / 2;
        while(j >= k) {
            j -= k;
            k /= 2;
        }
        if(j < k) j += k;
    }
}
void ntt(ll y[], int len, int on) {
    change (y, len);
    for(int h = 2; h <= len; h <<= 1) {
        ll wn = pow(G, (mod-1)/h);
        if(on == -1) wn = pow(wn, mod-2);
        for(int j = 0; j < len; j += h) {
            long long w = 1;
            for(int k = j; k < j + h / 2; k++) {
                long long u = y[k];
                long long t = w * y[k + h / 2] % mod;
                y[k] = (u + t) % mod;
                y[k+h/2] = (u - t + mod) % mod;
                w = w * wn % mod;
            }
        }
    }
    if(on == -1) {
        long long t = pow (len, mod - 2);
        for(int i = 0; i < len; i++)
            y[i] = y[i] * t % mod;
    }
}
***************************/

int a[N];
int pow2[N], r[N], f[N], F[N];

int main(){
//    freopen("in", "r", stdin);
//    freopen("outd", "w", stdout);
//    for(g[K]=pow(G,(P-1)/N),ng[K]=pow(g[K],P-2),i=K-1;~i;i--)
//        g[i]=(ll)g[i+1]*g[i+1]%P, ng[i]=(ll)ng[i+1]*ng[i+1]%P;
    for(inv[1]=inv[0]=1,i=2;i<N;i++) inv[i]=(ll)(P-inv[P%i])*(P/i)%P;

    for(f[0]=f[1]=r[0]=r[1]=pow2[0]=1, i=pow2[1]=2; i < N; i++){
        r[i] = (ll)inv[i]*r[i-1]%P;
        f[i] = (ll)i*f[i-1]%P;
        pow2[i] = (pow2[i-1]<<1)%P;
    }

    int t, ca = 1, n; scanf("%d", &t);
    while(t--){
        scanf("%d", &n);
        for(i = 1; i <= n; i++) scanf("%d", a+i);
        sort(a+1, a+n+1, greater<int>() );

        memset(B, 0, sizeof(B));
        memset(A, 0, sizeof(A));
        for(i = 1; i <= n; i++){
            B[i-1] = (ll)f[i-1]*pow2[n-i]%P*a[i]%P;
            A[i-1] = r[n-i];
        }

        int len = 1;
        while(len <= n+n) len <<= 1;
        NTT(B, len, 1), NTT(A, len, 1);
        for(int i = 0; i < len; i++)
            A[i] = B[i]*A[i]%P;
        NTT(A, len, -1);

        for(int i = 1; i <= n; i++){
            F[i] = A[n-2+i]*(ll)r[i-1]%P+F[i-1];
            if(F[i] >= P) F[i] %= P;
            printf("%d ", F[i]);
        }
        puts("");
    }
    return 0;
}

 以上代码蜜汁T，NTT()换成ntt()后蜜汁WA。

和AC代码对拍很久也没看出什么问题。