Advent of Code 2022

day_2.c

/**
 * Advent of Code 2022
 * Day 2: Rock Paper Scissors
 * https://adventofcode.com/2022/day/2
 *
 * http://codercorner.com/Modulo3.htm
 * (Index+1)%3 = (1 << Index1) & 3
 */
#include <stdlib.h>
#include <stdio.h>

extern int
main(int argc, char *argv[]) {
  unsigned s = 0;
  static const char in[] = "A Y\nB X\nC Z\n";
  for (int i = 0; i < 3; ++i) {
#if 0
    unsigned v = *(unsigned*)(in + i * 4) - 0xa582041;
    unsigned d = !(v^((v>>16)|(v<<16)))*3;
    unsigned w = (!((1<<(v&0x3))&3)^(v>>16)))*6;
    s += d + w + (v&0x3)+1;
#else
    unsigned x = *(unsigned*)(in + i * 4);
    unsigned k = ((x * 0xedc72f12u)) >> 28u;
    s += (unsigned)((0x396852417llu >> (k * 4u)) & 0xfllu);
#endif
  }
  printf("total: %d\n", s);
  return 0;
}

day_6.c

/**
 * Advent of Code 2022
 * Day 6: Tuning Trouble
 * https://adventofcode.com/2022/day/6
 */
/*
The problem statement is: given a string, find the first occurrence of a substring of given fixed length 4
in that string, where each of the characters in that substring are distinct. 
*/
#include <string.h>
#include <stdio.h>

extern int
main(void) {
  static const char *s = "hqhnqhqshhslswsffchfcfbblvlblqlggfwwqfwwqdddbbbhzhjjrqjqbjqjwqjwqwhwrrmcrrjqjjlllcvcrrnpptzpzmmswmmzrzjrrfcrfccpbpzzvrrdndllttwftwwgzzwhwggdvdnnlrnncscbcfcctchcdchdccztzgzjjtdtcdtcchrrgpgzgsgpsggvtvppdccfhcfclfcfdfnddlbbptbtdbtdtjdjgdjjzljlssgbgcgqcqzccfnftfjjsgstggsngsscvssjzjnjtntvnvssrqqhtqtvqtvvjbvvbnvvqvmvrmmdsdvdwwnbnvbnvvcgvcczcfzftfsfrfsfttldtdrrgrgmgbbdvvbqbhqbqlqsqbsbpbgbvgbgwwrswrwrwttvnnzdnzzwggrmrfmmvllzwlwzzlvlbvllgsllpnlnvncvcvqqrwwcmcczhchzczbccdwcwvwzwwvddlwlhljlqjqnncntnctczzmwmlmccpggljlssqswsmmpvmvwvrrcpcrprmprrtdrtdrrsjsmshmmdpdlppbnbvvmmflmmjvjhvhjvjsjbjwjvvblvbvlbbllwlslvljvlvdvdgvgcchnhpnhnvhhtfhhvssczztlzzgvvqqghqgqssdscsnsrsmrmmwgwmgmlmdmggbgzbgzgdzdzccghgfgddtntftddpdrdrmrjmmmzttqmttnwngggtgtqtqnqhnqqpnnntrntrnnshhjtjzzfqqblqqlblslflmlttcwtwzzrlrnrcrrrgtrrftfhthzhggwggvgvvfvddcnddfjddzqzrrvtrvrfrrgpgrgngsgddlmddzgzppdzzjzhjhjhqqbpbvvlrvrsvrvnrrsgsttndnbngnppmlppvgvfggvcvrvnnsnfnnfqfwwppnddrrfqqgbqqfmmlnlnngwgcgjgnjgjsgjgqjjnccdttpqttswwcgcmgmccrppmqmbbfwwvdwdfwfjwfjjblldsdrdvvgcvcwwllfpllcslsvssnvsnvvhnvnvwwcgwccslsbbnlbnbrrrtprptpdpdvdttgsgwswppcdchhqbqcbqbzbgbbstshthsttqgtqtpqqzhhwhghwwmbbdlbbtlltsllbvbnvvmqvqtvqvttlwtltmmrttwgtwwfdddwcchtchhbthbbclczzqbzzpvvwzwswggjddntnrnnwmnnbdbmbccqgqvvsnvvqbvbzvvzmvzzrfrlfrfhhdvddnmnnmhmqhhrhlrldljlbljjgqqvdvhhgmgvgddmmznndmmhssznsswvwdvdzdhhscssntnftfmmrggbmbmgmlltctbtbntnqqscqcscrcrhrlhhdchhzccvvbfvvpfffbwbsbjjmgmwgmgppjnpjphhlmhhpwwhwzhhhzbbzzcbchhpnnptpvphhsdsccffqbqllchlhlwlcljlppnccqsstzstswtwwljwjmmpttvqqspsjjclljqqlhqqtnnbrrsbrbjjllrmrjmjzmmclmclmmcvvbddhnnmhmbbwqqqhrqqtqmqbqdbdtdvvcscshccmffhqffdgdcgddljdjbdbjbdbrrtjjtnntpntpnpmnpmpgghffrnfrnnmdnmnhmmjcjffftrrttfwfvwvcwwrmwmpwmmnvntthmmgmbbcdclcppjhpjhjwwlppgsszqqwggmttfrfqflfsfmmmhchshmmjtjjgdjjnnsvsmsnwcgdfqljmnphlfdrhpggfqnhnszgpndhdqcgfhtdcgbsbtmhvnnrmqzqqcjdqndzbnrhwjvbvcldmnwltgpqbmstntnggtbqjzzqrfdsfttdfrcnsrpwrjrjqbgtjfmlwsrzdbdqvbtczgsjqhtgmctjfmdglfrsvqtgwpbqghzgzdfwzhbdhlmhdvhwjrdhhtjptvwpmjnmfcjdmdczmczvdqwvbgtvlwvwnvdlbqfshmlmvzzcmjbtpwpwgsqhfsgljzhbppcztfjdntzcvllqnzrqjwfjrlgvhmbpvbtqjrdzcsmcjzcdsmvcmhrbhgnscnfrfmscqsqpqplbrzhsrlsvvpmfdtdmtlrtvspmlljmfpshfmstjgnrrwmqlbnwbndcfdstrtqtnzpfqlcgrzmsnmhllljdgtmvftjttbwhqzcqwbwdbshgcqrptfjwbbfsjnvzztlbdchqrlbbrcnsswmhwphfwrbnvrncbrthprmltlwwlfpbqhdfqzwwcwjgqzdnvmhwpzpbtpwwvzcpfcsfqpwjljzzfwzmlfvhsccppzlzjlrvlpdtjpcptnvqjwtdbzrqwnfwmmjndflqqggczrfjlpdfjffctprnmhfdqvnzbfvhszzdmngnlmwzfdrbvlvjnmbllgrczssqcrhbmnpmqlrzgmqmhgsvcdlqnmlhlzvqzhnccbctslzlbcpdvqltqncpcrzwdchrqmwfwlcbcvfnnpjntfrznqdjsdtzqjjttddwvnfqmznhflblzvvtbwdzrrlqlmndzzzwnpbhhlvlbswfjtbnhlccscbnfgjtwbfdlwvzszwnwzhlbcdpvgqjcrpzsvvnfwqcqvrmhzhggvmzwggdpbfrdscjwhsdsbbjcnzldhzcvqtjrhsbfjlrlpvtcqhnnsvslfrdjvjhfhdcfzqchpvvhzbpqglqlrdttrdtndzhnzhtqndghtgmpsnhptprqzhbbdcrgmbvrvqmbptqgnmsccwmhrlpddvmhjntllwrzqwnsjchnblcgndjtmpswwgcstdftqcbhzgttrhnpvrhspjznhhvrlpdqbzzrvzjphcswhljdldvsrdhzltwgrcsvqwnhtqqjjrjgrplzmsnjhzrfbtqgdfgnbpvjrfzrrpdphgzrfbswdhzgbzswqtwwdtrvvswmjvwhqddfzjhgdqsfnwbmlcfwtmpldrdpwjwggbpmncvbghzjmpsqpvnmbhjfzzpsjdgmrtnndhzrphjzdbgrrnthtrfnspdngbdmwbnfjlsndqswfsvfqftqlgqjpfsfpmdbsjfrptvbpvflqgvlmmbchhghhrwmvdlrhlsdtvjjchwglcrwfsfnnbhjbtccbjsfwrbzrvgsbfnvzghhrqblqchjvdtrrbrwwwmfnczzmmrqdggsfrqbldbbfbbcthtsvpcnlbjjztwvhctbrjltqdwbzmrrfslbmjpnqwllbvjzgfsfqqtwbgwgclgdflshfhwggwdqlgbmdmdqglrtfwbddtsltmsvswhgjtqwtnrncpdzhnpfqcjnjzmtbjfzpjwgfbfggmsmfdhfbjctnhchpgfspthdbfpmvrmdbbspvwzqqwnmfwdnnblbcjszbccgflngnjjwsqshfbhjwgzrmvsgnrdbgwfhdvpmznpnvznfcqdclztcptjrrpbmpztwwbvlvtmngfhmfbfmrjbjzlrcvgllrlgthltstnwmffntqrwsrndlzqhztwpcwbdjjztgdzmgtthcvtvnjzzhvstfqhgddddgdsrbcqzqspjrncphhtbnslzphrtfqphffjrrlgwbrwqfzzqvzhnffcwvrncttgplshccglvchvlcbnlthhmzvcrfjvjqfsjjzzgqlpslfwngqnbgcwffpcqhlmlhvwssrpjbrcbftpzbbpptzrdqwpzpdjhtwbvwcqbfnwtflfgzgttglpcwdnzsmjffgfftdnpzlpszmzrrhvlzdfpgbzqlvvfslnndcmjvvpwzwcdzpcttfwbsdswmfqbbhbfbjvbvtspbbhmphzjsjcmmzpvvzhtvzlgwlqqvbnrgtszvghjfmchrwwhpmbsvfmgvqdtmvdtjppchbsgqrtgtnzczqmpgjdbmmflfpjbcdmhldwpgdtdvsbzhztjzfhcsbndfjntbldjnqwdffqspfnlplbtcdjtwdjhldtsdfrnmpfhzghnpcqlhhgblmqjvwhndqfbccvzzlbzbdprvcpwjjhrqnjptwssbjhgvpgtfzqwrzjvbdgwtnmptvdjrffcmbzmzcmrfbjv";
  int n = strlen(s);
  for (int j = 0; j + 3 < n; ++j) {
#if 1
    unsigned u = *(unsigned*)(s + j);
    unsigned m = (~u & 0x80808080);
    unsigned t0 = ((u ^ (0x01010100 * ss[0])) - 0x01010101) & m;
    unsigned t1 = ((u ^ (0x01010001 * ss[1])) - 0x01010101) & m;
    unsigned t2 = ((u ^ (0x01000101 * ss[2])) - 0x01010101) & m;
    unsigned t3 = ((u ^ (0x00010101 * ss[3])) - 0x01010101) & m;   
    if (!(t0|t1|t2|t3)) {
      printf("msg[%d] unique at %d\n", 0, j+4);
      break;
    }
#elif 0
    #define has0(v) (((v)-0x01010101u)&(~(v)&0x80808080u))
    #define rotl(x,r) ((x << r)|(x >>(32-r)))
    unsigned v = *(unsigned*)(s + j);
    unsigned t0 = has0(v^rotl(v,8));
    unsigned t1 = has0(v^rotl(v,16));
    unsigned t2 = has0(v^rotl(v,24));
    if (!(t0|t1|t2)) {
      printf("msg[%d] unique at %d\n", 0, j+4);
      break;
    }
#elif 0
    unsigned set = 0u;
    set |= 1u << ((ss[0]-'a') & 31u);
    set |= 1u << ((ss[1]-'a') & 31u);
    set |= 1u << ((ss[2]-'a') & 31u);
    set |= 1u << ((ss[3]-'a') & 31u);
    if (_mm_popcnt_u32(set) == 4) {
      printf("msg[%d] unique at %d\n", 0, j+4);
      break;
    }
#else
    if (ss[0] != ss[1] && ss[0] != ss[2] && ss[0] != ss[3] &&
        ss[1] != ss[2] && ss[1] != ss[3] && ss[2] != ss[3]) {
      printf("msg[%d] unique at %d\n", 0, j+4);
      break;  
    }
#endif
  }
  return 0;
}