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//Decodes Base64
#include <openssl/bio.h>
#include <openssl/evp.h>
#include <string.h>
#include <stdio.h>

int calcDecodeLength(const char* b64input) { //Calculates the length of a decoded base64 string
  int len = strlen(b64input);
  int padding = 0;

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OpenSSL Base64 Encoding: Binary Safe and Portable

Herewith is an example of encoding to and from base64 using OpenSSL's C library. Code presented here is both binary safe, and portable (i.e. it should work on any Posix compliant system e.g. FreeBSD and Linux).

License

The MIT License (MIT)

Copyright (c) 2013 Barry Steyn

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Introduction

These toy examples are for helping with understanding C/C++. There is an excellent C++ samples site which demonstrates many useful things.

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Migrating From SVN to Git

This gist details the following:

1. Converting a Subversion (SVN) repository into a Git repository
2. Purging the resultant Git repository of large files

Migrating from SVN to Git is roughly split into three steps:

1. Retrieve a list of SVN commit usernames

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BITS = ('0', '1')
ASCII_BITS = 8

def bit_list_to_string(b):
    """converts list of {0, 1}* to string"""
    return ''.join([BITS[e] for e in b])

def seq_to_bits(seq):
    return [0 if b == '0' else 1 for b in seq]

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class Solution {
public:
    void rotate(vector<vector<int> > &matrix) {
        int N = matrix.size()-1,
            temp = 0;
        
        for (int i=0; i < N; i++) {
            for (int j=0; j+i < N; j++) {
                
                //Only one temp variable is needed             

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/*
 * This is a classic backtracking algorithm. It is made difficult due to the following:
 * 1) There is a special case, namely 0
 * 2) Normally, backtracking employs a for loop, this needs a while loop. Therefore
 *    conditions for ending the recursion is not normal
 *
 * All ip addresses consist of octets, which is between 0 and 255. So any number within this
 * range should be selected for our ip address. If however we cannot pick such a number
 * then we must back track
 * Time Complexity O(n^2) Space O(1)

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Leetcode: Reverse Linked List II

http://oj.leetcode.com/problems/reverse-linked-list-ii/

Problem Description

Reverse a linked list from position m to n. Do it in-place and in one-pass.

For example: Given 1->2->3->4->5->NULL, m = 2 and n = 4,

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Flatten Binary Tree to Linked List

http://oj.leetcode.com/problems/flatten-binary-tree-to-linked-list/

Problem Description

Given a binary tree, flatten it to a linked list in-place.

For example, Given

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LeetCode Problem: Word Search\

http://oj.leetcode.com/problems/word-search/

Problem Description

Given a 2D board and a word, find if the word exists in the grid.

The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell may not be used more than once.

For example, Given board =