package me.ramswaroop.arrays;
/**
* Created by IntelliJ IDEA.
*
* @author: ramswaroop
* @date: 9/8/15
* @time: 11:34 PM
*/
public class FixedPoint {
/**
* Finds the FIXED POINT in an array {@param a} of n distinct integers sorted
* in ascending order. If there is no fixed point it returns -1.
* FIXED POINT in an array is an index i such that arr[i] is equal to i. Note that
* integers in array can be negative.
*
* @param a
* @return
*/
public static int findFixedPoint(int[] a) {
int low = 0, high = a.length - 1, mid;
while (low <= high) {
mid = (low + high) / 2;
if (a[mid] == mid) {
return mid;
} else if (a[mid] > mid) {
high = mid - 1;
} else {
low = mid + 1;
}
}
return -1;
}
public static void main(String a[]) {
System.out.println(findFixedPoint(new int[]{-10, -5, 0, 3, 7}));
System.out.println(findFixedPoint(new int[]{0, 2, 5, 8, 17}));
System.out.println(findFixedPoint(new int[]{-10, -5, 3, 4, 7, 9}));
}
}