package com.thealgorithms.misc;
import java.util.Arrays;
public final class RangeInSortedArray {
private RangeInSortedArray() {
}
public static void main(String[] args) {
assert Arrays.equals(sortedRange(new int[] {1, 2, 3, 3, 3, 4, 5}, 3), new int[] {2, 4});
assert Arrays.equals(sortedRange(new int[] {1, 2, 3, 3, 3, 4, 5}, 4), new int[] {5, 5});
assert Arrays.equals(sortedRange(new int[] {0, 1, 2}, 3), new int[] {-1, -1});
}
public static int[] sortedRange(int[] nums, int key) {
int[] range = new int[] {-1, -1};
alteredBinSearchIter(nums, key, 0, nums.length - 1, range, true);
alteredBinSearchIter(nums, key, 0, nums.length - 1, range, false);
return range;
}
public static void alteredBinSearch(int[] nums, int key, int left, int right, int[] range, boolean goLeft) {
if (left > right) {
return;
}
int mid = (left + right) >>> 1;
if (nums[mid] > key) {
alteredBinSearch(nums, key, left, mid - 1, range, goLeft);
} else if (nums[mid] < key) {
alteredBinSearch(nums, key, mid + 1, right, range, goLeft);
} else {
if (goLeft) {
if (mid == 0 || nums[mid - 1] != key) {
range[0] = mid;
} else {
alteredBinSearch(nums, key, left, mid - 1, range, goLeft);
}
} else {
if (mid == nums.length - 1 || nums[mid + 1] != key) {
range[1] = mid;
} else {
alteredBinSearch(nums, key, mid + 1, right, range, goLeft);
}
}
}
}
public static void alteredBinSearchIter(int[] nums, int key, int left, int right, int[] range, boolean goLeft) {
while (left <= right) {
final int mid = (left + right) >>> 1;
if (nums[mid] > key) {
right = mid - 1;
} else if (nums[mid] < key) {
left = mid + 1;
} else {
if (goLeft) {
if (mid == 0 || nums[mid - 1] != key) {
range[0] = mid;
return;
} else {
right = mid - 1;
}
} else {
if (mid == nums.length - 1 || nums[mid + 1] != key) {
range[1] = mid;
return;
} else {
left = mid + 1;
}
}
}
}
}
public static int getCountLessThan(int[] nums, int key) {
return getLessThan(nums, key, 0, nums.length - 1);
}
public static int getLessThan(int[] nums, int key, int left, int right) {
int count = 0;
while (left <= right) {
final int mid = (left + right) >>> 1;
if (nums[mid] > key) {
right = mid - 1;
} else if (nums[mid] <= key) {
count = mid + 1;
left = mid + 1;
}
}
return count;
}
}