#include <stddef.h>
#include <float.h>

#define SIMD_SIZE 8

inline double sqr(double x)
{
    return x*x;
}

size_t foo(double x[], double y[], size_t n, double tourx, double toury)
{
    double closedist[SIMD_SIZE];
    size_t closeidx[SIMD_SIZE];
    size_t i,j;
    for (i=0; i<SIMD_SIZE; i++) {
        closedist[i] = DBL_MAX;
        closeidx[i] = i;
    }
    for (j=SIMD_SIZE; j<n; j+=SIMD_SIZE) {
      double dist[SIMD_SIZE];
      for (i=0; i<SIMD_SIZE; i++)
        dist[i] = sqr(x[i+j]-tourx)+sqr(y[i+j]-toury);
      for (i=0; i<SIMD_SIZE; i++) {
        if (dist[i]<closedist[i]) {
          closedist[i]=dist[i];
        }
      }
      for (i=0; i<SIMD_SIZE; i++) {
        if (dist[i]<closedist[i]) {
          return j+i;
        }
      }
    }
    return n;
}