66 lines
1.0 KiB
C
66 lines
1.0 KiB
C
int in[] = {10, 32, -1, 567, 3, 18, 1, -51, 789, 0};
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main() {
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int i;
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sort(in, (sizeof in)/(sizeof in[0]));
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for (i = 0; i < (sizeof in)/(sizeof in[0]); i++) {
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putd(in[i]);
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putchar('\n');
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}
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return 0;
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}
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/* putd - output decimal number */
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putd(n) {
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if (n < 0) {
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putchar('-');
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n = -n;
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}
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if (n/10)
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putd(n/10);
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putchar(n%10 + '0');
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}
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int *xx;
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/* sort - sort a[0..n-1] into increasing order */
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sort(a, n) int a[]; {
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quick(xx = a, 0, --n);
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}
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/* quick - quicksort a[lb..ub] */
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quick(a, lb, ub) int a[]; {
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int k, partition();
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if (lb >= ub)
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return;
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k = partition(a, lb, ub);
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quick(a, lb, k - 1);
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quick(a, k + 1, ub);
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}
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/* partition - partition a[i..j] */
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int partition(a, i, j) int a[]; {
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int v, k;
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j++;
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k = i;
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v = a[k];
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while (i < j) {
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i++; while (a[i] < v) i++;
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j--; while (a[j] > v) j--;
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if (i < j) exchange(&a[i], &a[j]);
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}
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exchange(&a[k], &a[j]);
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return j;
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}
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/* exchange - exchange *x and *y */
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exchange(x, y) int *x, *y; {
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int t;
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printf("exchange(%d,%d)\n", x - xx, y - xx);
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t = *x; *x = *y; *y = t;
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}
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