tests/gcc/common/src/heapsort.c
/* -*- mode: c -*-
* $Id: heapsort.c,v 1.2 2003/12/30 01:21:23 davidw Exp $
* http://www.bagley.org/~doug/shootout/
*/
/* END COMMENT */
#include <stdlib.h>
#include <math.h>
#include <stdio.h>
#define IM 139968
#define IA 3877
#define IC 29573
double
gen_random(double max) {
static long last = 42;
return( max * (last = (last * IA + IC) % IM) / IM );
}
void
heapsort(int n, double *ra) {
int i, j;
int ir = n;
int l = (n >> 1) + 1;
double rra;
for (;;) {
if (l > 1) {
rra = ra[--l];
} else {
rra = ra[ir];
ra[ir] = ra[1];
if (--ir == 1) {
ra[1] = rra;
return;
}
}
i = l;
j = l << 1;
while (j <= ir) {
if (j < ir && ra[j] < ra[j+1]) { ++j; }
if (rra < ra[j]) {
ra[i] = ra[j];
j += (i = j);
} else {
j = ir + 1;
}
}
ra[i] = rra;
}
}
int
main(int argc, char *argv[]) {
int N = ((argc == 2) ? atoi(argv[1]) : 1);
double *ary;
int i;
/* create an array of N random doubles */
ary = (double *)malloc((N+1) * sizeof(double));
for (i=1; i<=N; i++) {
ary[i] = gen_random(1);
}
heapsort(N, ary);
printf("%.10f\n", ary[N]);
free(ary);
return(0);
}
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