Bitcoin transaction graph

I am trying to make bitcoin transaction graph, but I am not sure how to go about it. I have extracted the necessary data from blockchain like the sender, receiver, amount of bitcoins sent, transaction hash and the date and time when it first got included in the block. The format for which is shown below:-

TXID                                                                       Input Address                  Value               Output Address                    Time & Dates

363ec29e4fc43f97576423d0d522f5f0fc79c5c018c3a210c5644ab79a38041d                                        25.0301   [u'1CjPR7Z5ZSyWk6WtXvSFgkptmpoi4UM9BC']    2014-01-12 01:36:19

f264c5c36b624110201a27bd02883508d29dfe1f94975aa8cc652fb8bc1496a9 1AyHWFST4jhcdVs74Hd3pvCdafpktmiF8Y       299.0   [u'13vZBq8ayCzficfP3uwm52bctv5mSXKfM1']    2014-01-12 01:36:19

I am not sure what should be my first step towards constructing transaction graph. I am trying to use hadoopcryptoledger library available in Apache spark for doing so, but not sure how to use the result that I have extracted from blockchain for that. Do I first need to create a database to store my result?
The file that contains the above information is in .txt format. Any help would be appreciated.

How to unstuck a low-fee transaction with

I’ve sent a transaction from, but accidentally included too little fee. What can I do to cancel the transaction or speed up the transaction’s confirmation?

This is a complementary question to Why is my transaction not getting confirmed and what can I do about it? which answers the question’s broader implications and proposes mitigation mostly focused on Bitcoin Core.

Bitcoin and Smart Contracts

I have recently come across the features of ethereum and the idea of smart contracts.

I like the concept of smart contracts however as a currency, I much prefer the bitcoin to the ether.

Is there any way smart contracts could ever be utilised by bitcoin?

Problems restoring wallet

First of all .. yes im stupid.
Now .. I had some BTC a few years ago. Thought I had kept it safe, now I seem to have reinstalled the OS on that PC and wiped profile folder. I looked around for a wallet.dat file and found one, but it could also be a file of another crypto currency .. not sure, it’s so long ago I’m not sure what I did anymore but the date on the file seems on the old side (december 2013).
I installed Bitcoin Core (I used what existed before CORE came out .. just bitcoin afaik ?), I let it sync for a day and am now caught up.
I replaced the wallet.dat file and started the client again. First it took a few minutes rescanning, then crashed at 100% (???). I restarted client again, now it said it had to update the blockchain a bit more, it was at 99.9% and quickly finished.
Now it shows my wallet is empty, but it also tells me it is encrypted and locked. I tried unlocking from the debug console, but it tells me the pw is incorrect. This is weird because the only thing I’m sure of is that this is the correct password.
Is it possible the encryption type has changed through the years and I need to somehow upgrade my wallet.dat or something ?
Even without unlocking should I be able to see the balance at least ?
I know its also possible to have the private key saved somewhere (thats what I should have done, but what I have saved looks short to me, I assume its the password.)
Looking at the balance of 0 BTC i have a feeling this jsut means I’m screwed. I only have myself to blame. I’m still going to attempt to find another backup file, or attempt to restore deleted files from that disk, maybe there’s still something there.

Would an optimization proof-of-work problem where the entity with the lowest hash wins have any security weakness or other disadvantage?

I am wondering if there would be any security deficiencies if cryptocurrencies such as Bitcoin were to change their proof-of-work problems to optimization contests. For example, suppose Bitcoin were to change its proof-of-work problem to an optimization problem. In this scenario, the goal each instance of the proof-of-work problem would be to minimize the output of the hash function, and the winner of each block is the entity who finds the input with the lowest hash after 10 minutes. Would an optimization proof-of-work problem cause any security weaknesses, other deficiencies, or complications for the cryptocurrency? Are there any cryptocurrencies which use an optimization proof-of-work problem instead of a search problem as a proof-of-work?