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#include <stdio.h>#define MAX 100int flags[MAX] = {0};int urand(void){	int k, val;	for (k=0;k<MAX;++k)		if (flags[k] == 0)			break;	if (k == MAX)		return -1;	while (flags[val = rand() % MAX])		;	++flags[val];	return val;}int main(){	int k;	srand(time(0));	for (k = 0; k < MAX; ++k)		printf("%d ", urand());	printf("\n\n%d\n", urand());	return 0;}