153. Find Minimum in Rotated Sorted Array
Suppose a sorted array is rotated at some pivot unknown to you beforehand.
(i.e., 0 1 2 4 5 6 7
might become 4 5 6 7 0 1 2
).
Find the minimum element.
You may assume no duplicate exists in the array.
二分查找,如果mid小于最右侧,证明右边是sort好的,则最小值必定在左边。
如果mid大于等于最右侧,则证明左侧最小值被rotate到了右侧,则最小值必定在右侧。
public class Solution {
public int findMin(int[] num) {
if (num.length == 0) {
return Integer.MIN_VALUE;
}
int left = 0;
int right = num.length - 1;
int min = num[0];
while (left <= right) {
int mid = left + (right - left) / 2;
if (num[mid] <= num[right]) {
right = mid - 1;
} else {
left = mid + 1;
}
min = Math.min(min, num[mid]);
}
return min;
}
}