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public class FindMinimumInRotatedSortedArray {
public int findMin(int[] nums) {
if (nums == null || nums.length == 0) {
return 0;
}
if (nums.length == 1 || nums[0] < nums[nums.length - 1]) {
return nums[0];
}
return helper(0, nums.length - 1, nums);
}
private int helper(int start, int end, int[] nums) {
int result = nums[start];
while (start < end) {
if (nums[start] < nums[end]) {
result = nums[start];
break;
}
int middle = (start + end) / 2;
if (middle > 0 && nums[middle] < nums[middle - 1]) {
result = nums[middle];
break;
}
if (middle == start) {
result = Math.min(nums[start], nums[end]);
break;
}
if (nums[middle] > nums[start] && nums[middle] > nums[end]) {
start = middle + 1;
} else if (nums[middle] < nums[start] && nums[middle] < nums[end]) {
end = middle - 1;
}
}
return (start == end) ? nums[start] : result;
}
@Test
public void test() {
int[] nums = new int[]{2, 3, 4, 5, 1};
System.out.println(findMin(nums));
}
}
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