Submission #421403

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Source Code Expand

#define _CRT_SECURE_NO_WARNINGS
//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
//#define int ll
//#define endl "\n"
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
#define all(c) (c).begin(), (c).end()
#define loop(i,a,b) for(ll i=a; i<ll(b); i++)
#define rep(i,b) loop(i,0,b)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
template<class T> ostream & operator<<(ostream & os, vector<T> const &);
template<int n, class...T> typename enable_if<(n>=sizeof...(T))>::type _ot(ostream &, tuple<T...> const &){}
template<int n, class...T> typename enable_if<(n< sizeof...(T))>::type _ot(ostream & os, tuple<T...> const & t){ os << (n==0?"":" ") << get<n>(t); _ot<n+1>(os, t); }
template<class...T> ostream & operator<<(ostream & os, tuple<T...> const & t){ _ot<0>(os, t); return os; }
template<class T, class U> ostream & operator<<(ostream & os, pair<T,U> const & p){ return os << "(" << p.first << ", " << p.second << ") "; }
template<class T> ostream & operator<<(ostream & os, vector<T> const & v){ rep(i,v.size()) os << v[i] << (i+1==(int)v.size()?"":" "); return os; }
template<class T> inline bool chmax(T & x, T const & y){ return x<y ? x=y,true : false; }
template<class T> inline bool chmin(T & x, T const & y){ return x>y ? x=y,true : false; }
#ifdef DEBUG
#define dump(...) (cerr<<#__VA_ARGS__<<" = "<<mt(__VA_ARGS__)<<" ["<<__LINE__<<"]"<<endl)
#else
#define dump(...)
#endif
// ll const mod = 1000000007;
// ll const inf = 1LL<<60;

typedef double Real;
typedef complex<Real> Complex;

Real const PI = acos(-1);

namespace FFT {
    Complex z[1<<20];
    int len;
    vector<Complex> fastFourierTransform(vector<Complex> & f, int inv = 0){
        int n = f.size();
        if(n==1) return f;
        vector<Complex> f0(n>>1), f1(n>>1);
        rep(i,n>>1) f0[i] = f[i<<1], f1[i] = f[i<<1|1];
        f0 = fastFourierTransform(f0,inv), f1 = fastFourierTransform(f1,inv);
        int k = len/n, m = n/2-1;
        rep(i,n) f[i] = f0[i&m] + z[inv ? len-k*i-1 : k*i] * f1[i&m];
        return f;
    }

    vector<Complex> convolution(vector<Complex> g, vector<Complex> h){
        int n_ = max(g.size(), h.size());
        int n = 1;
        while(n < n_) n<<=1;
        g.resize(n);
        h.resize(n);
        len = n+1;
        rep(i,len) z[i] = polar<Real>(1,2*PI/n*i);
        vector<Complex> g_ = fastFourierTransform(g);
        vector<Complex> h_ = fastFourierTransform(h);
        vector<Complex> f_(n);
        rep(i,n) f_[i] = g_[i]*h_[i];
        vector<Complex> res = fastFourierTransform(f_,1);
        rep(i,n) res[i] /= n;
        return res;
    }
}

signed main(){
    int n;
    scanf("%d",&n);
    vector<Complex> g(n*2+1), h(n*2+1);
    rep(i,n){
        int a,b;
        scanf("%d%d",&a,&b);
        g[i+1] = a, h[i+1] = b;
    }
    vector<Complex> f = FFT::convolution(g,h);
    for(int i=1;i<=n*2;i++) printf("%d\n",(int)(f[i].real()+0.5));
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:73:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
                   ^
./Main.cpp:77:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&a,&b);
                            ^

Judge Result