Submission #728033

#	Time	Username	Problem	Language	Result	Execution time	Memory
728033		rainboy	Guess the number (BOI20_guess)	C11	100 / 100	1 ms	276 KiB

Guess

#include <stdio.h>

int main() {
	int n, lower, upper;

	scanf("%d", &n);
	lower = 1, upper = n;
	while (1) {
		int a, c;

		a = (lower + upper) / 2;
		printf("? %d\n", a), fflush(stdout);
		scanf("%d", &c);
		if (c < 0)
			lower = a + 1;
		else if (c > 0)
			upper = a - 1;
		else {
			printf("= %d\n", a), fflush(stdout);
			break;
		}
	}
	return 0;
}

Compilation message (stderr)

Guess.c: In function 'main':
Guess.c:6:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
    6 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
Guess.c:13:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |   scanf("%d", &c);
      |   ^~~~~~~~~~~~~~~

• Subtask 1: 29 / 29
• Subtask 2: 71 / 71