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Copy pathSearch.java
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102 lines (89 loc) · 2.93 KB
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/**
* Search algorithms for arrays of cards.
*/
public class Search {
/**
* Sequential search.
*/
public static int search(Card[] cards, Card target) {
for (int i = 0; i < cards.length; i++) {
if (cards[i].equals(target)) {
return i;
}
}
return -1;
}
/**
* Binary search (iterative version).
*/
public static int binarySearch(Card[] cards, Card target) {
int low = 0;
int high = cards.length - 1;
while (low <= high) {
System.out.println(low + ", " + high);
int mid = (low + high) / 2; // step 1
int comp = cards[mid].compareTo(target);
if (comp == 0) { // step 2
return mid;
} else if (comp < 0) { // step 3
low = mid + 1;
} else { // step 4
high = mid - 1;
}
}
return -1;
}
/**
* Binary search (recursive version).
*/
public static int binarySearchRec(Card[] cards, Card target,
int low, int high) {
System.out.println(low + ", " + high);
if (high < low) {
return -1;
}
int mid = (low + high) / 2; // step 1
int comp = cards[mid].compareTo(target);
if (comp == 0) { // step 2
return mid;
} else if (comp < 0) { // step 3
return binarySearchRec(cards, target, mid + 1, high);
} else { // step 4
return binarySearchRec(cards, target, low, mid - 1);
}
}
/**
* Make an array of 52 cards.
*/
public static Card[] makeDeck() {
Card[] cards = new Card[52];
int index = 0;
for (int suit = 0; suit <= 3; suit++) {
for (int rank = 1; rank <= 13; rank++) {
cards[index] = new Card(rank, suit);
index++;
}
}
return cards;
}
/**
* Demonstrates how to call the search methods.
*/
public static void main(String[] args) {
Card[] cards = makeDeck();
Card jack = new Card(11, 0);
Card fake = new Card(15, 1);
System.out.println("Sequential search");
System.out.println(search(cards, jack));
System.out.println();
System.out.println("Binary search");
System.out.println(binarySearch(cards, jack));
System.out.println();
System.out.println("Failed binary search");
System.out.println(binarySearch(cards, fake));
System.out.println();
System.out.println("Recursive binary search");
System.out.println(binarySearch(cards, jack));
System.out.println();
}
}