Add part 2 for day 1 (didn't initially notice there was a part 2)

Dependencies

• [2] XBZHQ672 Day 1 solution

Change contents

• file addition: day1p2.cpp (----------)
  [2.7]
  + #include <iostream>

  + #include <fstream>

  +

  + struct cll {

  + char c;

  + cll *next;

  + ~cll() {

  + delete next;

  + }

  + };

  +

  + int cll_length(cll *node) {

  + int r = 0;

  + while(node) {

  + r++;

  + node = node->next;

  + }

  + return r;

  + }

  +

  + cll* cll_rotate(cll *root, int dist) {

  + cll *ns = root;

  + for(int i = 0; i < dist; i++) {

  + ns = ns->next;

  + }

  + cll *cs = ns;

  + cll *ct = NULL;

  + cll *nroot = NULL;

  + while(cs) {

  + cll *n = new cll();

  + n->c = cs->c;

  + if(ct) {

  + ct->next = n;

  + } else {

  + nroot = n;

  + }

  + ct = n;

  + cs = cs->next;

  + }

  + cs = root;

  + while(cs != ns) {

  + cll *n = new cll();

  + n->c = cs->c;

  + ct->next = n;

  + ct = n;

  + cs = cs->next;

  + }

  + ct->next = NULL;

  + return nroot;

  + }

  +

  + int main(int argc, char** args) {

  + std::ifstream input = std::ifstream(args[1]);

  + cll *root = NULL;

  + cll *current = NULL;

  + char c;

  + while(input.get(c)) {

  + if(c >= '0' && c <= '9') {

  + if(current) {

  + current->next = new cll();

  + current = current->next;

  + } else {

  + root = new cll();

  + current = root;

  + }

  + current->c = c;

  + }

  + }

  + current->next = NULL;

  + cll *root2 = cll_rotate(root, cll_length(root) / 2);

  + unsigned long long tally = 0;

  + current = root;

  + cll *current2 = root2;

  + while(current->next) {

  + if(current->c == current2->c) {

  + tally += current->c - '0';

  + }

  + current = current->next;

  + current2 = current2->next;

  + }

  + delete root;

  + delete root2;

  + std::cout << tally << "\n";

  + }