Algorithm-DataStructure
JAVA SE 8 API
- java.util.Array
static int binarySearch(int[] a, int fromIndex,int toIndex, int key)Searches a range of the specified array of ints for the specified value using the binary search algorithm. The range must be sorted prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.
Parameters:
a - the array to be searched
fromIndex - the index of the first element (inclusive) to be searched
toIndex - the index of the last element (exclusive) to be searched
key - the value to be searched for
Return the index of the search key,, if it is contained in the array within the specified range; otherwise, (-(insertion point) - 1)
- Example: Russian Doll Envelopes
Use Binary Search to find insert position.
static void sort(T[] a, Comparator<? super T> cSorts the specified array of objects according to the order induced by the specified comparator. All elements in the array must be
mutually comparable by the specified comparator (that is,c.compare(e1, e2)).
- java.util Interface Comparator<T>
Type Parameters:
T - the type of objects that maybe compared by the comparator.
int compare(T o1, T o2)Compares its two arguments for order. Returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.
Lambda Expression:http://www.java67.com/2014/11/java-8-comparator-example-using-lambda-expression.html
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Example: Russian Doll Envelopes, Merge K Sorted List, Skyline Problem
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java.util.PriorityQueue<E>
Type Parameters:
E - the type of elements held in this collection
PriorityQueue(int initialCapacity, Comparator<? super E> comparator)Creates a PriorityQueue with the specified initial capacity that orders its elements according to the specified comparator.
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Example: Merge K Sorted Lists, Skyline Problem
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java.util **Interface List<E> ** ------SuperInterface Collection<E>
boolean addAll(Collection<? extends E> c)Appends all of the elements in the specified collection to the end of this list, in the order that they are returned by the specified collection's iterator (optional operation).
Average-Related Preblem Analysis
array: [a1, a2, a3, a4, a5, a6]
average > minimum value && average < maximum value
Maintain a sum array, each time add the difference between current element and average.
[0, a1 - average, a1 - average + a2 - average, a1 - average + a2 - average + a3 - average, .....
sum[0, m] - sum[0, n] = sum[n, m] -- consider it as setAlgorithm-DataStructure