Jimexist

#import <stdio.h>

void swap(int *a, int *b) {
    int tmp = *a;
    *a = *b;
    *b = tmp;
}

/* Precondition: n > 0 */
void reverse(int arr[], int n) {

Jimexist

public class Solution {
    
    private Map<Integer, int[]> pows = new HashMap<Integer, int[]>();
    
    {
        pows.put(1, new int[]{1, 1, 1, 0});
    }
    
    private int[] pow(int n) {
        if (pows.containsKey(n)) return pows.get(n);

Jimexist

public class Solution {
    public String multiply(String num1, String num2) {
        return toString(mult(toIntArray(num1), toIntArray(num2)));
    }
    
    private int[] toIntArray(String s) {
        int[] result = new int[s.length()];
        for (int i=0; i<result.length; ++i) {
            result[i] = Character.digit(s.charAt(s.length()-1-i), 10);
        }

Jimexist

import Test.QuickCheck

takeR :: Int -> [a] -> [a]
takeR n _ | n <= 0 = []
takeR n l | otherwise = go (drop n l) l
                        where go [] y = y
                              go (_:xs) (_:ys) = go xs ys

prop_length s n = (length s >= n && n >= 0) ==> length (takeR n s) == n
  where types = (s :: [Char], n :: Int )

Jimexist

public class Solution {

    private static final int MATCHED = 1, DELETED = 1, INSERTED = 1;

    public int minDistance(String word1, String word2) {
        if (word1.length() == 0) return word2.length() * INSERTED;
        if (word2.length() == 0) return word1.length() * DELETED;
        if (word1.equals(word2)) return 0; // not much used though
        
        final int rows = word1.length();

Jimexist

import java.util.*;

public class Solution {

    public String countAndSay(int n) {
        List<Integer> i = new ArrayList<Integer>();
        i.add(1);

        while (--n > 0) {
            i = say(i);

Jimexist

public class Solution {
    public ArrayList<ArrayList<Integer>> combine(int n, int k) {
        final ArrayList<ArrayList<Integer>> result = new ArrayList<ArrayList<Integer>>();
        if (k == 0) {
            result.add(new ArrayList<Integer>());
            return result;
        }
        for (int i=n; i>=1; --i) {
            for (ArrayList<Integer> ai : combine(i-1, k-1)) {
                ai.add(i);

Jimexist

public class Solution {
    public ArrayList<ArrayList<Integer>> subsetsWithDup(int[] num) {
        Arrays.sort(num);
        final ArrayList<ArrayList<Integer>> result = new ArrayList<ArrayList<Integer>>();
        if (num.length == 0) {
            result.add(new ArrayList<Integer>());
            return result;
        }
        btrack(num, new boolean[num.length], 0, result);
        return result;        

Jimexist

import java.util.*;

public class Derangement {

    public static void main(String[] args) {
        List<Integer> list = new ArrayList<>();
        for (int i=0; i<4; ++i) {
            list.add(i);
        }
        for (List<Integer> li : derangement(list)) {

Jimexist

import java.util.*;

public class Permutations {
    private Permutations() {
    }

    public static void main(String[] args) {
        for (List<Integer> li : permutate(Arrays.asList(1, 2, 4, 9))) {
            System.out.println(li);
        }