| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package org.apache.datasketches; |
| |
| /** |
| * Contains common equality binary search algorithms. |
| * |
| * @author Lee Rhodes |
| */ |
| public final class BinarySearch { |
| |
| /** |
| * Binary Search for the index of the exact float value in the given search range. |
| * If -1 is returned there are no values in the search range that equals the given value. |
| * @param arr The given ordered array to search. |
| * @param low the index of the lowest value of the search range |
| * @param high the index of the highest value of the search range |
| * @param v the value to search for |
| * @return return the index of the value, if found, otherwise, return -1; |
| */ |
| public static int find(final float[] arr, final int low, final int high, final float v) { |
| int lo = low; |
| int hi = high; |
| while (lo <= hi) { |
| final int mid = lo + (hi - lo) / 2; |
| if (v < arr[mid]) { hi = mid - 1; } |
| else { |
| if (v > arr[mid]) { lo = mid + 1; } |
| else { return mid; } |
| } |
| } |
| return -1; |
| } |
| |
| /** |
| * Binary Search for the index of the exact double value in the given search range. |
| * If -1 is returned there are no values in the search range that equals the given value. |
| * @param arr The given ordered array to search. |
| * @param low the index of the lowest value of the search range |
| * @param high the index of the highest value of the search range |
| * @param v the value to search for |
| * @return return the index of the value, if found, otherwise, return -1; |
| */ |
| public static int find(final double[] arr, final int low, final int high, final double v) { |
| int lo = low; |
| int hi = high; |
| while (lo <= hi) { |
| final int mid = lo + (hi - lo) / 2; |
| if (v < arr[mid]) { hi = mid - 1; } |
| else { |
| if (v > arr[mid]) { lo = mid + 1; } |
| else { return mid; } |
| } |
| } |
| return -1; |
| } |
| |
| /** |
| * Binary Search for the index of the exact long value in the given search range. |
| * If -1 is returned there are no values in the search range that equals the given value. |
| * @param arr The given ordered array to search. |
| * @param low the index of the lowest value of the search range |
| * @param high the index of the highest value of the search range |
| * @param v the value to search for |
| * @return return the index of the value, if found, otherwise, return -1; |
| */ |
| public static int find(final long[] arr, final int low, final int high, final long v) { |
| int lo = low; |
| int hi = high; |
| while (lo <= hi) { |
| final int mid = lo + (hi - lo) / 2; |
| if (v < arr[mid]) { hi = mid - 1; } |
| else { |
| if (v > arr[mid]) { lo = mid + 1; } |
| else { return mid; } |
| } |
| } |
| return -1; |
| } |
| |
| } |