ichaos

/*
 * Magic code to print china map.
 * The original idea is from International Obfuscated C Code test, check more here.
 * http://stackoverflow.com/questions/3533348/how-does-this-code-generate-the-map-of-india
 */
#include <stdio.h>
int main(){int a,b,c; for (b = c = 10; (a = 
 	"-FIGURE?,China *CJ Hello Folks,\
 	b&M\"D(G*>/#\";,B1:0=12<924;554D\
 	*76`<W#!?UEZ>YCWEWFTJOP$%CXAX@Z?\

ichaos

#include <stdio.h>

//duff's device
void duffs_device(const char *src, int length, char *dst) {
	int n = (length + 7) / 8;
	switch (length % 8) {
		case 0:	do {	*dst++ = *src++;
		case 7:			*dst++ = *src++;
		case 6:			*dst++ = *src++;
		case 5:			*dst++ = *src++;

ichaos

/**
 * Lessons Learned:
 *  1. Encapsulate basic and usual operations so that
 *    we can write code like write English sentence
 *  2. Using template, metaprogramming
 *  3. readable code !
 */ 

//Eat one character of special type 
template<typename CharacterClass>

ichaos

/*
 * check if a string is within a given levenshtein distance to any string in a dictionary
 * credit: Leo Polovets
 * see more on quora: https://www.quora.com/Algorithms/Which-is-the-best-programming-algorithm-that-you-have-ever-created
 */
#include <iostream>
#include <string>
#include <algorithm>
#include <cstdlib>

ichaos

/*  the Sieve of Eratosthenes */
#include <cmath>
#include <vector>

using namespace std;

bool[] findPrimes(int n) {
  vector<bool> isPrimes(n + 1, true);
  isPrimes[0] = false;
  isPrimes[1] = false;

ichaos

#include <algorithm>

using namespace std;

struct people {
    int s;
    int b;
    int i;
    
    bool operator<(const people &o) const {

ichaos

bool isPerfectSquare(int x) {
  int sqr = Math.sqrt(x);
  
  return x == sqr * sqr;
}

bool isPerfectSquareFaster(int x) {
  if (x < 0) return false;
  int h = x & 0xf;
  if (h == 0 || h == 0x1 || h == 0x4 || h == 0x9) {

ichaos

Divide and conquer

The maximum subarray problem

Brute-force: just try every possible pair of buy and sell dates in which buy dates precedes the sell dates
then find the maximum. O(n2)

Divide and conquer

Linear method

ichaos

Chapter 1: What's money?
Money is trust. Money means you trust the men or entity who print the papers and
believe later they will receive your papers and
give you the equal value commodity you want.

Chapter 2: What's bond?
It's still trust. And it also means borrowing money from future.
规模和 diversification of risk

ichaos

/**
 * Array is different with pointer, although it is used like a pointer.
 * Here is an example
 */
#include <stdio.h>

int main() {
  int a[5];
  
  printf("%p\n", a);