AoC 2021 day 14

#include <Arduino.h>
#include "data.h"

struct keyvalue {
   char key;
   uint64_t value = 0;
};

const int listSize = sizeof rules / sizeof rules[0];
char ruleList[listSize][3] = {"\0"};
char charList[listSize][3] = {"\0"};;
uint64_t countList[listSize] = {0};
uint64_t bufferList[listSize] = {0};
keyvalue countMap[listSize];

void pairInsertion(){
  for (int i = 0; i < listSize; i++) {
    if(countList[i]== 0)continue;

    char buf1[3]= {'\0'};
    buf1[0] = ruleList[i][0];
    buf1[1] = charList[i][0];

    char buf2[3]= {'\0'};
    buf2[0] = charList[i][0];
    buf2[1] = ruleList[i][1];

    for (int j = 0; j < listSize; j++) {
      if(strcmp(buf1, ruleList[j]) == 0)bufferList[j]+=countList[i];
      if(strcmp(buf2, ruleList[j]) == 0)bufferList[j]+=countList[i];
    }
  }

  for (int i = 0; i < listSize; i++) {
    countList[i] = bufferList[i];
    bufferList[i] = 0;
  }
}

void initData(){

  int index = 0;
  for(auto r : rules){
    strcpy(ruleList[index],r[0]);
    strcpy(charList[index],r[1]);
    index++;
  };

  for (size_t i = 0; i < sizeof str / sizeof str[0] -1; i++)
  {
    char buf[3]= {'\0'};
    buf[0] = str[i];
    buf[1] = str[i + 1];

    for (int j = 0; j < listSize; j++)
    {
        if(strcmp(ruleList[j], buf) == 0)countList[j]++;
    }
  }
}

int strIndex = 0;
void addKeyValue(char key, uint64_t value){
  bool inList = false;
  for(auto &kv : countMap){
    if(kv.key == key){
      kv.value+=value;
      inList = true;
      break;
    }
  }
  if(!inList){
    countMap[strIndex].key = key;
    countMap[strIndex++].value = value;
  }
}

char *uint64_to_string(uint64_t input)
{
    static char result[21] = "";
    // Clear result from any leftover digits from previous function call.
    memset(&result[0], 0, sizeof(result));
    // temp is used as a temporary result storage to prevent sprintf bugs.
    char temp[21] = "";
    char c;
    uint8_t base = 10;

    while (input)
    {
        int num = input % base;
        input /= base;
        c = '0' + num;

        sprintf(temp, "%c%s", c, result);
        strcpy(result, temp);
    }
    return result;
}

void setup() {

  Serial.begin(9600);
  while(!Serial);

  initData();

  for (int x = 0; x < 40 ; x++) {
    pairInsertion();
  }

  for (int i = 0; i < listSize; i++) {
    addKeyValue(ruleList[i][1],countList[i]);
  };
  addKeyValue(str[0],1);

  uint64_t minCount=INFINITY;
  uint64_t maxCount=0;

  for(auto &kv : countMap){
    if(kv.key != NULL){
      maxCount = max(kv.value, maxCount);
      minCount = min(kv.value, minCount);
    }
  }
  Serial.println( "------" );
  Serial.println( uint64_to_string ( maxCount - minCount ));
}

void loop() {
  // put your main code here, to run repeatedly:
}