View difference between Paste ID: esAwP5tj and KEjzuTgH

-//AC Just a few more triangles! https://open.kattis.com/problems/moretriangles
+//FFT
-#include <iostream>
+//[email protected]
-#include <cmath>
+//ref: AC Just a few more triangles! https://open.kattis.com/problems/moretriangles
-#include <vector>
+
 #include <ccomplex>
 #include <complex>
-#include <algorithm>
+
-#include <map>
+
 typedef double ld;
 const ld PI = acos(-1.L);
 typedef complex<ld> Complex;
 
 //precomputing these saves 50% time
 map<pair<int, int>, Complex> wns;
 void FFTinit(int N){
 	for (int i = 1; i <= N; i *= 2)
 		for (int dir = -1; dir <= 1; dir += 2)
 			wns[make_pair(i, dir)] = polar((ld)1, dir * 2 * PI / i);
 }
 
 // *** Fast Fourier Transform (Recursive), ubc codearchive, heavily modified... ***
 //array pointers instead of vectors, calculations done in-place
 void rfft(int n, Complex* a, Complex* y, int dir = 1, int stride = 1) {
 	if (n == 1) { y[0] = a[0]; return; }
 	Complex wn = wns[make_pair(n, dir)], w = 1;
 //	Complex wn = polar((ld)1, dir * 2 * PI / n), w = 1; //precomputed instead
 	rfft(n / 2, a, y, dir, stride * 2);
 	rfft(n / 2, a + stride, y + n / 2, dir, stride * 2);
 	for (int k = 0; k < n / 2; k++, w *= wn) {
 		Complex y1 = y[k] + w*y[n / 2 + k];
 		Complex y2 = y[k] - w*y[n / 2 + k];
 		y[k + n / 2] = y2;
 		y[k] = y1;
 	}
 }
 //end code archive
 void ifft(int n, Complex* a, Complex* y) {
 	for (int i = 0; i < n; i++) a[i] /= ld(n);
 	rfft(n, a, y, -1);
 }
 
 /** example:
 
-typedef long long ll;
+
 
-int main(){
+
-	ll n, res=0;
+
-	cin >> n; ll sz = n + n - 1;
+
 	//convolution
 	for (ll i = 0; i < n; i++) tmp[i] = v[i];
 	rfft(N, &tmp[0], &c[0]);
-	for (ll i = 1; i < n; i++) v[(i*i) % n] = v[(i*i) % n] + (ld)1;
+
 	ifft(N, &tmp[0], &c[0]);
 
 */