49 lines
1.4 KiB
Haxe
49 lines
1.4 KiB
Haxe
package funkin.backend.utils;
|
|
|
|
/**
|
|
* All types of utils only usable in a sorted array.
|
|
*/
|
|
class SortedArrayUtil {
|
|
/**
|
|
* Gets the index of a possible new element of an Array of T using an efficient algorithm.
|
|
* @param array Array of T to check in
|
|
* @param getVal Function that returns the position value of T
|
|
* @return Index
|
|
*/
|
|
public static inline function binarySearch<T>(array:Array<T>, val:Float, getVal:T->Float):Int {
|
|
if (array.length <= 0) return 0; // if the array is empty, it should be equal to zero (the beginning)
|
|
if (getVal(array[0]) > val) return 0; // in case its the minimum
|
|
if (getVal(array[array.length-1]) < val) return array.length; // in case its the maximum
|
|
|
|
// binary search
|
|
var iMin:Int = 0;
|
|
var iMax:Int = array.length-1;
|
|
|
|
var i:Int = 0;
|
|
var mid:Float;
|
|
while(iMin <= iMax) {
|
|
i = Math.floor((iMin + iMax) / 2);
|
|
mid = getVal(array[i]);
|
|
if (mid < val)
|
|
iMin = i+1
|
|
else if (mid > val)
|
|
iMax = i-1;
|
|
else {
|
|
iMin = i;
|
|
break;
|
|
}
|
|
}
|
|
return iMin;
|
|
}
|
|
|
|
/**
|
|
* Adds to a sorted array, using binary search.
|
|
* @param array Array to add to
|
|
* @param val Value to add
|
|
* @param getVal Function that returns the value that needs to be sorted
|
|
*/
|
|
public static inline function addSorted<T>(array:Array<T>, val:T, getVal:T->Float) {
|
|
if (val != null)
|
|
array.insert(binarySearch(array, getVal(val), getVal), val);
|
|
}
|
|
} |