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Merged
realDuYuanChao merged 2 commits into from
Nov 24, 2020
Merged

Added Jump Search #57

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e79fd1d
add jump search
realDuYuanChao Nov 24, 2020
07eb5ae
Formatted with Google Java Formatter
Nov 24, 2020
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16 changes: 16 additions & 0 deletions src/main/java/com/examplehub/maths/SumOfFactorial.java
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package com.examplehub.maths;

/** Calculate 1! + 2! + 3! + ... n! */
public class SumOfFactorial {
public static int sum(int n) {
return sum(1, n);
}

public static int sum(int i, int n) {
if (i == n) {
return n;
} else {
return i + i * sum(i + 1, n);
}
}
}
32 changes: 32 additions & 0 deletions src/main/java/com/examplehub/searches/JumpSearch.java
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package com.examplehub.searches;

public class JumpSearch implements Search {
@Override
public int search(int[] numbers, int key) {
int length = numbers.length;
int steps = (int) Math.floor(Math.sqrt(length));
int prev = 0;
while (numbers[Math.min(steps, length) - 1] < key) {
prev = steps;
steps += (int) Math.floor(Math.sqrt(length));
if (prev >= length) {
return -1;
}
}
while (numbers[prev] < key) {
prev++;
if (prev == Math.min(steps, length)) {
return -1;
}
}
if (numbers[prev] == key) {
return prev;
}
return -1;
}

@Override
public <T extends Comparable<T>> int search(T[] array, T key) {
return 0;
}
}
16 changes: 16 additions & 0 deletions src/test/java/com/examplehub/maths/SumOfFactorialTest.java
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package com.examplehub.maths;

import static org.junit.jupiter.api.Assertions.*;

import org.junit.jupiter.api.Test;

class SumOfFactorialTest {
@Test
void testSum() {
assertEquals(1, SumOfFactorial.sum(1));
assertEquals(3, SumOfFactorial.sum(2));
assertEquals(9, SumOfFactorial.sum(3));
assertEquals(33, SumOfFactorial.sum(4));
assertEquals(153, SumOfFactorial.sum(5));
}
}
27 changes: 27 additions & 0 deletions src/test/java/com/examplehub/searches/JumpSearchTest.java
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package com.examplehub.searches;

import static org.junit.jupiter.api.Assertions.*;

import java.util.stream.IntStream;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

class JumpSearchTest {
private Search search;

@BeforeEach
void setup() {
search = new JumpSearch();
}

@Test
void testLinearSearch() {
int[] ints = IntStream.range(0, 10).toArray();
for (int i = 0; i < ints.length; ++i) {
assertEquals(i, search.search(ints, i));
}
assertEquals(-1, search.search(ints, 10));
assertEquals(-1, search.search(ints, 100));
assertEquals(-1, search.search(ints, -1));
}
}