Submission #774979

#	Time	Username	Problem	Language	Result	Execution time	Memory
774979		hgmhc	Guess the number (BOI20_guess)	C++17	100 / 100	1 ms	292 KiB

Guess

#include <bits/stdc++.h>
using namespace std;

bool f(int x) {
    printf("? %d\n", x);
    fflush(stdout);
    int q; scanf("%d", &q);
    if (q == 0) {
        printf("= %d\n", x);
        fflush(stdout);
        exit(0);
    }
    else if (q < 0) return true;
    else return false;
}

int main() {
    int n; scanf("%d", &n);
    int a = 1, b = n;
    while (a <= b) {
        int m = (a+b)/2;
        if (f(m)) a = m+1;
        else b = m-1;
    }
}

Compilation message (stderr)

Guess.cpp: In function 'bool f(int)':
Guess.cpp:7:17: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    7 |     int q; scanf("%d", &q);
      |            ~~~~~^~~~~~~~~~
Guess.cpp: In function 'int main()':
Guess.cpp:18:17: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |     int n; scanf("%d", &n);
      |            ~~~~~^~~~~~~~~~

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