Created
February 11, 2019 10:08
-
-
Save eutkin/3547004d5ba30dbe8cb3734a1e531682 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
package com.company; | |
import java.math.BigInteger; | |
import java.util.List; | |
import java.util.Map; | |
import java.util.function.Function; | |
import java.util.stream.Collectors; | |
import java.util.stream.Stream; | |
import static java.util.stream.Collectors.toList; | |
public class Test { | |
public static void main(String[] args) { | |
one(); | |
System.out.println(two(5, 2)); // 10 | |
System.out.println(two(5, 3)); // 10 | |
System.out.println(two(5, 5)); // 1 | |
System.out.println(three("Hello World! Hello, my friend! All Friend meet you.")); | |
// [friend, hello, all, world, meet, my, you] | |
} | |
public static void one() { | |
for (int i = 0; i < 100; i++) { | |
if (i % 2 == 0 && i % 7 == 0) { | |
System.out.println("TwoSeven"); | |
} else if | |
(i % 2 == 0) { | |
System.out.println("Two"); | |
} else if (i % 7 == 0) { | |
System.out.println("Seven"); | |
} else { | |
System.out.println(i); | |
} | |
} | |
} | |
public static BigInteger two(int m, int r) { | |
if (m < r || m < 0 || r < 0) { | |
throw new RuntimeException(); | |
} | |
int diff = m - r; | |
if (diff == 0) return BigInteger.ONE; | |
/* | |
m = 5, r = 2. Берем 3 числа, m = 5, r = 2 и diff = m - r = 3. Факториал самого маленького | |
сокращается. Самое маленькое число + 1 тоже сокращается. | |
1) вычисляем разницу между m и r, diff = m - r. | |
2) если diff = 0, возвращаем 1 | |
3) Вычисляем минимальное число (min). Оно сокращается, поэтому факториал для него считать не надо. | |
4) Вычисляем два факториала. (min - 1)! и (от min - 1 до m)!. Отнимаем 1, так как есть и там и там. | |
2! * 3 * 4 * 5 3 * 4 * 5 4 * 5 | |
------------------- = ------------- = --------- = 10 | |
2! * 3! 1 * 2 * 3 1 * 2 | |
*/ | |
int min = diff < r ? r : diff; | |
BigInteger f1 = factorial(min - 1); | |
BigInteger f3 = factorial(min + 1, m); | |
return f3.divide(f1); | |
} | |
public static List<String> three(String text) { | |
return Stream.of(text.split("\\s+|,|-|\\.|\\?|!")) | |
.map(String::toLowerCase) | |
.collect(Collectors.groupingBy(Function.identity(), Collectors.counting())) | |
.entrySet() | |
.stream() | |
.sorted(Map.Entry.<String, Long>comparingByValue().reversed()) | |
.map(Map.Entry::getKey) | |
.filter(s -> !s.isEmpty()) | |
.collect(toList()); | |
} | |
public static BigInteger factorial(final int start, final int number) { | |
if (number == 0) return BigInteger.ONE; | |
BigInteger result = BigInteger.ONE; | |
for (int i = start; i <= number; i++) { | |
result = result.multiply(BigInteger.valueOf(i)); | |
} | |
return result; | |
} | |
public static BigInteger factorial(final int number) { | |
return factorial(1, number); | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment