Maximum Number in Mountain Sequence
Given a mountain sequence ofnintegers which increase firstly and then decrease, find the mountain top.
Have you met this question in a real interview?
Yes
Example
Givennums=[1, 2, 4, 8, 6, 3]return8
Givennums=[10, 9, 8, 7], return10
Note:二分 直接比较 nums[mid] > nums[mid + 1] 即可找到top number
public int mountainSequence(int[] nums) {
if (nums == null || nums.Length == 0){
return -1;
}
int start = 0,end = nums.Length - 1;
while (start + 1 < end) {
int mid = start + (end - start) / 2;
if (nums[mid] > nums[mid + 1]) {
end = mid;
} else {
start = mid;
}
}
if (nums[end] > nums[start]){
return nums[end];
}
else {
return nums[start];
}
}