--- /dev/null
+#include <stdio.h>
+#include <stdlib.h>
+#include <complex.h>
+#include <math.h>
+
+int readPaulicoeffs(int* alpha, int* beta, int* gamma, int* delta, int numqubits);
+complex double Gausssum1d(int quadraticcoeff, int linearcoeff);
+complex double Kroneck(int arg);
+
+// order of matrix elements is [row][column]!!!
+
+int main()
+{
+
+ int i;
+
+ int N; // number of qubits
+ scanf("%d", &N);
+
+ int alpha[N], beta[N], gamma[N], delta[N];
+
+ double complex summand, sum;
+
+ while(readPaulicoeffs(alpha, beta, gamma, delta, N)) {
+
+ // for(i=0; i<N; i++)
+ // printf("%d %d %d %d\n", alpha[i], beta[i], gamma[i], delta[i]);
+
+ sum = 1.0 + 0.0*I;
+
+ for(i=0; i<N; i++) {
+ summand = 0.0*I;
+ summand += 0.5*(Kroneck(gamma[i]+delta[i]) + pow(-1,beta[i])*Kroneck(gamma[i]+delta[i])
+ +csqrt(I)*cpow(-I,delta[i])*Kroneck(alpha[i]+beta[i]) + csqrt(-I)*cpow(I,delta[i])*Kroneck(alpha[i]+beta[i]));
+ sum *= summand;
+ }
+ //printf("%lf+%lfI\n", creal(sum), cimag(sum));
+ printf("%lf\n", cabs(creal(sum)));
+
+
+ }
+
+ return 0;
+}
+
+complex double Kroneck(int arg)
+{
+ arg = (arg+1)%2; // output 1 if argument is 0 mod 2 and 0 otherwise
+ return ((complex double)arg);
+}
+
+complex double Gausssum1d(int quadraticcoeff, int linearcoeff)
+{
+ // we assume coeffs are either 0 or 1
+ quadraticcoeff %= 2;
+ linearcoeff %= 2;
+
+ if(quadraticcoeff == 0)
+ if(linearcoeff == 0)
+ return 2.0+0.0*I;
+ else
+ return 0.0*I;
+ else
+ if(linearcoeff == 0)
+ return 1.0+1.0*I;
+ else
+ return 1.0-1.0*I;
+
+}
+
+int readPaulicoeffs(int *alpha, int *beta, int *gamma, int *delta, int numqubits)
+{
+
+ int i;
+
+ if(scanf("%d %d %d %d", &alpha[0], &beta[0], &gamma[0], &delta[0]) != EOF) {
+ for(i=1; i<numqubits; i++) {
+ scanf("%d %d %d %d", &alpha[i], &beta[i], &gamma[i], &delta[i]);
+ }
+ return 1;
+ } else
+ return 0;
+
+}
+
+
+