37 lines
842 B
C
37 lines
842 B
C
#include <stdio.h>
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#include <stdlib.h>
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size_t rprint(char *s, int *x, int len)
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{
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#define sep (a > s ? "," : "") /* use comma except before first output */
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#define ol (s ? 100 : 0) /* print only if not testing for length */
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int i, j;
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char *a = s;
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for (i = j = 0; i < len; i = ++j) {
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for (; j < len - 1 && x[j + 1] == x[j] + 1; j++);
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if (i + 1 < j)
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a += snprintf(s?a:s, ol, "%s%d-%d", sep, x[i], x[j]);
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else
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while (i <= j)
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a += snprintf(s?a:s, ol, "%s%d", sep, x[i++]);
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}
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return a - s;
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#undef sep
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#undef ol
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}
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int main()
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{
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int x[] = { 0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
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25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
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37, 38, 39 };
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char *s = malloc(rprint(0, x, sizeof(x) / sizeof(int)) + 1);
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rprint(s, x, sizeof(x) / sizeof(int));
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printf("%s\n", s);
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return 0;
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}
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