LeetCode in Kotlin
374. Guess Number Higher or Lower
Easy
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
Solution
/*
* The API guess is defined in the parent class.
* @param num your guess
* @return -1 if num is higher than the picked number
* 1 if num is lower than the picked number
* otherwise return 0
* fun guess(num:Int):Int {}
*/
class Solution : GuessGame() {
fun guessNumber(n: Int): Int {
var start = 0
var end = n
while (start <= end) {
val mid = start + (end - start) / 2
if (guess(mid) == 0) {
return mid
} else if (guess(mid) == -1) {
end = mid - 1
} else {
start = mid + 1
}
}
return -1
}
}