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SearchMountainArray.java

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import java.util.Arrays;

public class SearchMountainArray {

public static void main(String[] args) {

int[] nums = {1,2,3,4,5,4,3,2,1};

int target = 2;

int peak = mountainArray(nums);

int asc = binarySearch(nums,target,0,peak);

int dsc = binarySearch(nums,target,peak,nums.length-1);

int[] nums1 = {asc,dsc};

System.out.println(Arrays.toString(nums1));

}

public static int mountainArray(int[] nums){

int start = 0;

int end = nums.length-1;

while(start < end) {

int mid = (start + end) / 2;

if (nums[mid] > nums[mid + 1]) {

end = mid;

} else if(nums[mid] <= nums[mid + 1]) {

start = mid + 1;

}

}

return start;

}

public static int binarySearch(int[] nums, int target,int start,int end){

boolean isAsc = nums[start] < nums[end];

while(start<=end){

int mid = (start+end)/2;

if(nums[mid]==target) {

return mid;

}

if(isAsc) {

if(target>nums[mid]){

start = mid+1;

}else{

end = mid-1;

}

}else {

if(target<nums[mid]){

start = mid+1;

}else{

end = mid-1;

}

}

}

return -1;

}

}