P1733 Guess the Number (Interactive I/O Version)

The judge will choose an integer in the range $[1,10^9]$. You should write a program to guess it. You may ask at most $50$ questions. For each query, you may ask the judge about one integer in $[1,10^9]$. The judge returns: - $0$, if it is the answer (i.e., the number chosen by the judge), after which the program must stop querying. - $-1$, if it is less than the answer. - $1$, if it is greater than the answer. For each query, you must print to standard output an integer in $[1,10^9]$, then print a newline and flush the output buffer. You can flush the buffer using: - For C/C++: `fflush(stdout)`. - For C++: `std::cout

N/A

# Hint #### Constraints Let $n$ be the answer. - For $50\%$ of the testdata, it is guaranteed that $n \leq 51$. - For $100\%$ of the testdata, it is guaranteed that $1 \leq n \leq 10^9$. [Interactive library for this problem](https://www.luogu.com.cn/paste/uaece7av). ###

#### Constraints Let $n$ be the answer. - For $50\%$ of the testdata, it is guaranteed that $n \leq 51$. - For $100\%$ of the testdata, it is guaranteed that $1 \leq n \leq 10^9$. [Interactive library for this problem](https://www.luogu.com.cn/paste/uaece7av). #### Hint Reference program for this problem: ```cpp #include #include int main() { for (int l = 1, r = 1000000000, mid = (l + r) >> 1, res; l > 1) { std::cout res; if (res == 0) { return 0; } else if (res == -1) { l = mid + 1; } else if (res == 1) { r = mid - 1; } else { puts("OvO, I AK IOI"); // this statement will never be executed. } } return 0; } ``` Translated by ChatGPT 5