adventofcode2022/day21/monkeysagain.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

#define BUFFER_SIZE 64
#define MAX_MONKEYS 4096

enum monkeyType {
    CONSTANT,
    ARITHMETIC
};

enum operand {
    ADDITION,
    SUBTRACTION,
    MULTIPLICATION,
    DIVISION
};

typedef struct monkey {
    char name[4];
    char leftOperandName[4];
    char rightOperandName[4];
    enum monkeyType type;
    struct monkey *leftOperand;
    struct monkey *rightOperand;
    enum operand op;
    long long number;
    int hasValue;
} MONKEY;

long long getNumber(MONKEY);

int main() {
    char buf[BUFFER_SIZE], *p, c;
    memset(buf, 0, BUFFER_SIZE);
    p = buf;
    MONKEY monkeys[MAX_MONKEYS], root;
    memset(monkeys, 0, MAX_MONKEYS * sizeof(MONKEY));
    int monkey_count = 0;
    char op;

    while ((c = getchar()) != EOF) {
        *p++ = c;
        if (c == '\n') {
            if (sscanf(buf, "%c%c%c%c: %c%c%c%c %c %c%c%c%c", &monkeys[monkey_count].name[0], &monkeys[monkey_count].name[1], &monkeys[monkey_count].name[2], &monkeys[monkey_count].name[3], &monkeys[monkey_count].leftOperandName[0], &monkeys[monkey_count].leftOperandName[1], &monkeys[monkey_count].leftOperandName[2], &monkeys[monkey_count].leftOperandName[3], &op, &monkeys[monkey_count].rightOperandName[0], &monkeys[monkey_count].rightOperandName[1], &monkeys[monkey_count].rightOperandName[2], &monkeys[monkey_count].rightOperandName[3]) == 13) {
                switch (op) {
                    case '+':
                        monkeys[monkey_count].op = ADDITION;
                        break;
                    case '-':
                        monkeys[monkey_count].op = SUBTRACTION;
                        break;
                    case '*':
                        monkeys[monkey_count].op = MULTIPLICATION;
                        break;
                    case '/':
                        monkeys[monkey_count].op = DIVISION;
                        break;
                }
                monkeys[monkey_count].type = ARITHMETIC;
            } else {
                sscanf(buf, "%c%c%c%c: %lli", &monkeys[monkey_count].name[0], &monkeys[monkey_count].name[1], &monkeys[monkey_count].name[2], &monkeys[monkey_count].name[3], &monkeys[monkey_count].number);
                monkeys[monkey_count].type = CONSTANT;
                monkeys[monkey_count].hasValue = 1;
            }
            monkey_count++;
            memset(buf, 0, BUFFER_SIZE);
            p = buf;
        }
    }
    // Change names to pointers in monkeys
    for (int i = 0; i < monkey_count; i++) {
        if (monkeys[i].type == ARITHMETIC) {
            for (int j = 0; j < monkey_count; j++) {
                if (monkeys[i].leftOperandName[0] == monkeys[j].name[0] && monkeys[i].leftOperandName[1] == monkeys[j].name[1] && monkeys[i].leftOperandName[2] == monkeys[j].name[2] && monkeys[i].leftOperandName[3] == monkeys[j].name[3]) {
                    monkeys[i].leftOperand = &monkeys[j];
                }
                if (monkeys[i].rightOperandName[0] == monkeys[j].name[0] && monkeys[i].rightOperandName[1] == monkeys[j].name[1] && monkeys[i].rightOperandName[2] == monkeys[j].name[2] && monkeys[i].rightOperandName[3] == monkeys[j].name[3]) {
                    monkeys[i].rightOperand = &monkeys[j];
                }
            }
        }
    }

    // Get the shouted number
    //
    // Find 'root'
    for (int i = 0; i < monkey_count; i++) {
        if (monkeys[i].name[0] == 'r' && monkeys[i].name[1] == 'o' && monkeys[i].name[2] == 'o' && monkeys[i].name[3] == 't') {\
            root = monkeys[i];
        }
    }
    printf("%lli\n", getNumber(root));

    // Good old bruteforce for part 2
    // Find human
    MONKEY *human;
    for (int i = 0; i < monkey_count; i++) {
        if (monkeys[i].name[0] == 'h' && monkeys[i].name[1] == 'u' && monkeys[i].name[2] == 'm' && monkeys[i].name[3] == 'n') {\
            human = &monkeys[i];
        }
    }

    long long myNumber = 3759566892641;
    human->hasValue = 1;
    human->type = CONSTANT;
    human->number = myNumber;
    int found = 0;

    printf("%lli, %lli\n", getNumber(*root.leftOperand), getNumber(*root.rightOperand));
    printf("%lli\n", myNumber);
//    do {
//        // Reset all arithmetic monkeys
//        for (int i = 0; i < monkey_count; i++) {
//            if (monkeys[i].type == ARITHMETIC) {
//                monkeys[i].hasValue = 0;
//            }
//        }
//        human->number = myNumber++;
//        long long left = getNumber(*root.leftOperand);
//        // Reset all arithmetic monkeys
//        for (int i = 0; i < monkey_count; i++) {
//            if (monkeys[i].type == ARITHMETIC) {
//                monkeys[i].hasValue = 0;
//            }
//        }
//        long long right = getNumber(*root.rightOperand);
//
//        found = left == right;
//    } while (!found); 
//
//    printf("%lli\n", myNumber-1);
}

long long getNumber(MONKEY monkey) {
    // If previuosly calculated or constant
    if (monkey.hasValue == 1) {
        return monkey.number;
    }

    long long result = 0;
    switch (monkey.op) {
        case ADDITION:
            result = getNumber(*monkey.leftOperand) + getNumber(*monkey.rightOperand);
            break;
        case SUBTRACTION:
            result = getNumber(*monkey.leftOperand) - getNumber(*monkey.rightOperand);
            break;
        case MULTIPLICATION:
            result =  getNumber(*monkey.leftOperand) * getNumber(*monkey.rightOperand);
            break;
        case DIVISION:
            result = getNumber(*monkey.leftOperand) / getNumber(*monkey.rightOperand);
            break;
    }

    monkey.hasValue = 1;
    monkey.number = result;
    return result;
}