Discussion on: Advent of Code 2019 Solution Megathread - Day 2: 1202 Program Alarm

fn part_a(mut input: Vec<u32>) -> u32 {
    input[1] = 12;
    input[2] = 2;

    let mut i: usize = 0;
    while i < input.len() {
        if i % 4 == 0 {
            let opcode = input[i];
            if opcode == 99 {
                break;
            }
            let index_1 = input[i + 1] as usize;
            let index_2 = input[i + 2] as usize;
            let index_3 = input[i + 3] as usize;

            if opcode == 1 {
                input[index_3] = input[index_1] + input[index_2];
            } else if opcode == 2 {
                input[index_3] = input[index_1] * input[index_2];
            }
        }
        i = i + 1;
    }

    input[0]
}

fn part_b(input: Vec<u32>) -> u32 {
    let mut i = 0;
    let mut j = 0;
    while i < 100 {
        let mut input = input.clone();

        if exec_intcode_program(input, i, j) == 19690720 {
            return 100 * i + j;
            break;
        }

        if j == 99 {
            i = i + 1;
            j = 0;
        }
        j = j + 1;
    }

    0
}
fn exec_intcode_program(input: Vec<u32>, addl_inp_1: u32, addl_inp_2: u32) -> u32 {
    let mut input = input.clone();

    input[1] = addl_inp_1;
    input[2] = addl_inp_2;

    let mut i: usize = 0;
    while i < input.len() {
        if i % 4 == 0 {
            let opcode = input[i];
            if opcode == 99 {
                break;
            }
            let index_1 = input[i + 1] as usize;
            let index_2 = input[i + 2] as usize;
            let index_3 = input[i + 3] as usize;

            if opcode == 1 {
                input[index_3] = input[index_1] + input[index_2];
            } else if opcode == 2 {
                input[index_3] = input[index_1] * input[index_2];
            }
        }
        i = i + 1;
    }

    input[0]
}