ichaos

为什么要设计？
审美是一种本能需求。
偷懒也是。

互联网的未来？
帮助创造有价值的信息，帮助获得有价值的信息。信息和金融对经济同等重要。

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);

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

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

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

#include <algorithm>

using namespace std;

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

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

/*
 * 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

/**
 * 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

#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++;