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FindInRotatedSorted.java
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84 lines (58 loc) · 1.59 KB
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package com.vinay.practice.lc;
// https://leetcode.com/problems/search-in-rotated-sorted-array/
public class FindInRotatedSorted {
public static void main(String[] args) {
// TODO Auto-generated method stub
// int nums[] = {3,5,1};
int nums[] = {1,1,3};
int target = 0;
// int target = 3;
int pos = -1;
// find pivot
// then search in left or right of pivot
int pivot = findPivot(nums);
if (pivot == -1) {
pos = binarySearch(nums, 0, nums.length-1, target);
} else if (nums[pivot] == target) {
System.out.println("The target element was found at: " + pivot);
} else if (target >= nums[0]) {
pos = binarySearch(nums, 0, pivot-1, target);
} else {
pos = binarySearch(nums, pivot+1, nums.length-1, target);
}
System.out.println("The target element was found at: " + pos);
}
public static int findPivot(int arr[]) {
int start = 0;
int end = arr.length-1;
while(start <= end) {
int mid = start + (end-start)/2;
if(mid < end && arr[mid] > arr[mid+1]) {
return mid;
}
if(mid > start && arr[mid] < arr[mid-1]) {
return mid-1;
}
if(arr[start] >= arr[mid]) {
end = mid - 1;
} else { // if(arr[start] < arr[mid-1])
start = mid + 1;
}
}
return -1;
}
public static int binarySearch(int[] arr, int start, int end, int target) {
while(start <= end) {
//System.out.println("s");
int mid = start + (end-start) / 2;
if(target < arr[mid]) {
end = mid-1;
} else if(target > arr[mid]) {
start = mid+1;
} else {
return mid;
}
}
return -1;
}
}