Algorithm
Problem Name: 374. Guess Number Higher or Lower
We are playing the Guess Game. The game is as follows:
I pick a number from 1 to n. You have to guess which number I picked.
Every time you guess wrong, I will tell you whether the number I picked is higher or lower than your guess.
You call a pre-defined API int guess(int num), which returns three possible results:
-1: Your guess is higher than the number I picked (i.e.num > pick).1: Your guess is lower than the number I picked (i.e.num < pick).0: your guess is equal to the number I picked (i.e.num == pick).
Return the number that I picked.
Example 1:
Input: n = 10, pick = 6 Output: 6
Example 2:
Input: n = 1, pick = 1 Output: 1
Example 3:
Input: n = 2, pick = 1 Output: 1
Constraints:
1 <= n <= 231 - 11 <= pick <= n
Code Examples
#1 Code Example with Java Programming
Code -
Java Programming
public class Solution extends GuessGame {
public int guessNumber(int n) {
int start = 1;
int end = n;
while (start < = end) {
int mid = start + (end - start) / 2;
int result = guess(mid);
if (result == -1) {
end = mid - 1;
} else if (result == 1) {
start = mid + 1;
} else {
return mid;
}
}
return -1;
}
}
Input
n = 10, pick = 6
Output
6
#2 Code Example with C# Programming
Code -
C# Programming
namespace LeetCode
{
public class _0374_GuessNumberHigherOrLower
{
private readonly int number;
public _0374_GuessNumberHigherOrLower(int number)
{
this.number = number;
}
public int GuessNumber(int n)
{
int lo = 1, hi = n;
while (lo < = hi)
{
var mid = lo + (hi - lo) / 2;
var compare = guess(mid);
if (compare == 0) return mid;
else if (compare == -1) hi = mid - 1;
else lo = mid + 1;
}
return -1;
}
private int guess(int num)
{
if (num < number) return 1;
else if (num > number) return -1;
else return 0;
}
}
}
Input
n = 10, pick = 6
Output
6