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package books;
/**
* @program JavaBooks
* @description: 旋转数组的最小数字
* @author: mf
* @create: 2019/08/23 10:18
*/
/*
把一个数组最开始的若干个元素搬到数组的末尾，我们称之
为数组的旋转。输入一个递增排序的数组是的一个旋转，输出旋转
数组的最小元素。例如{3, 4, 5, 1, 2}为{1, 2, 3, 4, 5}的
一个旋转，该数组的最小值为1。
{0, 1, 1, 1, 1, ,1, 1}
*/
public class T11 {
public static void main(String[] args) {
int[] arr = {3, 4, 5, 1, 2};
System.out.println(findMin2(arr));
}
/**
*
* @param arr
* @return 坐标
*/
public static int findMin(int[] arr) {
int p1 = 0;
int p2 = arr.length - 1;
int mid = p1;
while (arr[p1] >= arr[p2]) {
if (p2 - p1 == 1) {
mid = p2;
break;
}
mid = p1 + ((p2 - p1) >> 1);
// 提高代码健壮性，若是出现arr[p1] arr[p2] mid三者相等
if (arr[p1] == arr[p2] && arr[p1] == mid) {
return ergodic(arr, p1, p2);
}
if (arr[p1] < arr[mid]) {
p1 = mid;
} else {
p2 = mid;
}
}
return mid;
}
public static int ergodic(int[] arr, int p1, int p2) {
int res = 0;
for (int i = p1; i <= p2; i++) {
if (res > arr[i]) {
res = arr[i];
}
}
return res;
}
/**
* 分析数组规律，单指针即可
* @param arr
* @return
*/
public static int findMin2(int[] arr) {
if (arr.length == 0) return 0;
if (arr.length == 1) return arr[0];
int a = arr[0];
for (int i = 1; i < arr.length; i++) {
if (a > arr[i]) {
return arr[i];
} else {
a = arr[i];
}
}
return 0;
}
}