101 lines
2.2 KiB
Odin
101 lines
2.2 KiB
Odin
package main
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import "core:math"
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import "core:slice"
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import "core:strconv"
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import "core:strings"
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import "core:bytes"
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import "core:fmt"
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import "core:os"
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import "../util"
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PREAMBLE_LEN :: 25
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is_sum_of_two :: proc(target_number: i64, numbers: []i64) -> bool {
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for num1, idx in numbers {
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for num2 in numbers[idx+1:] {
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if num1 + num2 == target_number do return true
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}
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}
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return false
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}
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part_1 :: proc(lines: []string) {
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result: i64 = 0
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numbers := make([]i64, len(lines))
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for line, idx in lines {
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ok: bool
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numbers[idx], ok = strconv.parse_i64(line); assert(ok)
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}
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idx := PREAMBLE_LEN
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for number in numbers[PREAMBLE_LEN:] {
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if !is_sum_of_two(number, numbers[idx-PREAMBLE_LEN:idx]) {
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result = number
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break
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}
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idx += 1
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}
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fmt.printfln("Part 1: %d", result)
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}
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part_2 :: proc(lines: []string) {
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result: i64 = 0
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numbers := make([]i64, len(lines))
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for line, idx in lines {
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ok: bool
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numbers[idx], ok = strconv.parse_i64(line); assert(ok)
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}
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invalid_number: i64
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idx := PREAMBLE_LEN
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for number in numbers[PREAMBLE_LEN:] {
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if !is_sum_of_two(number, numbers[idx-PREAMBLE_LEN:idx]) {
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invalid_number = number
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break
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}
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idx += 1
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}
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min_idx: i64 = 0
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max_idx: i64 = 0
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outer: for _ in numbers {
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contiguous_sum: i64 = 0
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max_idx = min_idx
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for num in numbers[min_idx:] {
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contiguous_sum += num
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if contiguous_sum == invalid_number {
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max := slice.max(numbers[min_idx:max_idx+1])
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min := slice.min(numbers[min_idx:max_idx+1])
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result = max + min
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break outer
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} else if contiguous_sum > invalid_number {
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break
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}
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max_idx += 1
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}
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min_idx += 1
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}
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fmt.printfln("Part 2: %d", result)
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}
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main :: proc() {
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context.allocator = context.temp_allocator
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defer free_all(context.temp_allocator)
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INPUT :: #load("input.txt", string)
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lines := strings.split(INPUT, "\n")
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lines = lines[:len(lines)-1]
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part_1(lines)
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part_2(lines)
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}
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