Closest Number in Sorted Array
37% Accepted
Given a target number and an integer array A sorted in ascending order,
find the index i in A such that A[i] is closest to the given target.
Return -1 if there is no element in the array.
Have you met this question in a real interview? Yes
Example
Given [1, 2, 3] and target = 2, return 1.
Given [1, 4, 6] and target = 3, return 1.
Given [1, 4, 6] and target = 5, return 1 or 2.
Given [1, 3, 3, 4] and target = 2, return 0 or 1 or 2.
Note
There can be duplicate elements in the array, and we can return any of the indices with same value.
Challenge
O(logn) time complexity.
Tags Expand
- Binary Search
public class Solution {
/**
* @param A an integer array sorted in ascending order
* @param target an integer
* @return an integer
*/
public int closestNumber(int[] A, int target) {
// Write your code here
int start = 0;
int end = A.length - 1;
int result;
while (start + 1 < end) {
int mid = start + (end - start) / 2;
if (A[mid] > target) {
end = mid;
} else if (A[mid] < target) {
start = mid;
} else {
return mid;
}
}
int minStart = Math.abs(A[start] - target);
int minEnd = Math.abs(A[end] - target);
if (minStart > minEnd) {
return end;
} else {
return start;
}
}
}