#include <stdio.h>

/* remove s2 chars from s1 */
void
squeeze(char s1[], char s2[])
{
	int i, j, k, b;
	for (i = j = 0; s1[i] != '\0'; ++i) {
		b = 0;
		for (k = 0; s2[k] != '\0'; ++k) {
			if (s1[i] == s2[k]) {
				b = 1;
			}
		}
		if (b == 0) {
			s1[j++] = s1[i];
		}
	}
	s1[j] = '\0';
}

/* return first index in s1 where any char in s2 */
int
any(char s1[], char s2[])
{
	int i, j;
	for (i = 0; s1[i] != '\0'; ++i) {
		for (j = 0; s2[j] != '\0'; ++j) {
			if (s1[i] == s2[j]) {
				return i;
			}
		}
	}
	return -1;
}

int
main()
{
	char s1[] = "foobar";
	char s2[] = "a";
	// squeeze(s1, s2);
	printf("%d\n", any(s1, s2));
	return 0;
}