UVa 00621- Secret Research (case analysis for only 4 possible outputs)

Link: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=8&page=show_problem&problem=562
Sol:

#include <cstdio>
	#include <cstring>
	using namespace std;
	int main() {
	int tc;
	char s[2000];
	scanf("%d", &tc);
	while (tc--) {
	scanf("%s", s);
	int len = strlen(s);
	if (strcmp(s, "1") == 0 || strcmp(s, "4") == 0 || strcmp(s, "78") == 0)
	printf("+\n");
	else if (s[len - 1] == '5' && s[len - 2] == '3')
	printf("-\n");
	else if (s[0] == '9' && s[len - 1] == '4')
	printf("*\n");
	else if (s[0] == '1' && s[1] == '9' && s[2] == '0')
	printf("?\n");
	else
	printf("+\n");
	}
	return 0;
	}