diff --git a/2020/1/README.md b/2020/1/README.md new file mode 100644 index 0000000..a6007e1 --- /dev/null +++ b/2020/1/README.md @@ -0,0 +1,29 @@ +## --- Day 1: Report Repair --- + +After saving Christmas [five years in a row](/events), you've decided to take a vacation at a nice resort on a tropical island. Surely, Christmas will go on without you. + +The tropical island has its own currency and is entirely cash-only. The gold coins used there have a little picture of a starfish; the locals just call them __stars__. None of the currency exchanges seem to have heard of them, but somehow, you'll need to find fifty of these coins by the time you arrive so you can pay the deposit on your room. + +To save your vacation, you need to get all __fifty stars__ by December 25th. + +Collect stars by solving puzzles. Two puzzles will be made available on each day in the Advent calendar; the second puzzle is unlocked when you complete the first. Each puzzle grants __one star__. Good luck! + +Before you leave, the Elves in accounting just need you to fix your __expense report__ (your puzzle input); apparently, something isn't quite adding up. + +Specifically, they need you to __find the two entries that sum to `2020`__ and then multiply those two numbers together. + +For example, suppose your expense report contained the following: + +``` +1721 +979 +366 +299 +675 +1456 +``` + +In this list, the two entries that sum to `2020` are `1721` and `299`. Multiplying them together produces `1721 * 299 = 514579`, so the correct answer is `514579`. + +Of course, your expense report is much larger. __Find the two entries that sum to `2020`; what do you get if you multiply them together?__ + diff --git a/2020/1/input.txt b/2020/1/input.txt new file mode 100644 index 0000000..b9b4050 --- /dev/null +++ b/2020/1/input.txt @@ -0,0 +1,200 @@ +1036 +1897 +1256 +1080 +1909 +1817 +1759 +1883 +1088 +1841 +1780 +1907 +1874 +1831 +1932 +1999 +1989 +1840 +1973 +1102 +1906 +1277 +1089 +1275 +1228 +1917 +1075 +1060 +1964 +1942 +2001 +1950 +1181 +1121 +1854 +1083 +1772 +1481 +1976 +1805 +1594 +1889 +1726 +1866 +798 +1739 +1709 +1946 +1948 +1808 +1836 +1849 +1465 +1066 +1943 +664 +1894 +1993 +1061 +1225 +1589 +1916 +1885 +1998 +1470 +1668 +1666 +1499 +1437 +1986 +1127 +1875 +1132 +1888 +1877 +1046 +1982 +1265 +1757 +1848 +1786 +1638 +1958 +1015 +1013 +1552 +1742 +1850 +1016 +1839 +558 +1826 +1261 +1988 +1545 +1078 +1963 +1967 +1951 +1086 +1947 +1880 +1903 +1994 +1167 +1736 +1041 +1652 +1040 +1033 +1179 +1844 +1861 +1488 +1962 +1135 +1347 +1187 +1777 +1598 +1803 +1147 +1760 +1926 +1898 +1923 +1865 +1313 +1924 +1023 +1576 +1715 +1391 +1346 +1882 +2000 +1024 +1143 +1065 +1560 +1029 +1119 +1966 +1022 +1931 +1512 +1049 +1929 +1312 +1069 +1159 +1053 +1249 +1074 +1983 +1761 +1868 +195 +24 +1331 +1636 +1020 +1034 +1671 +708 +1699 +1900 +1927 +1829 +301 +1832 +1042 +1896 +1928 +1032 +1992 +2005 +1955 +1047 +1068 +1001 +1052 +1744 +1845 +1208 +1018 +1859 +1342 +1823 +1758 +2007 +1241 +1893 +1876 +1984 +1655 +1534 +1150 +1789 +1870 diff --git a/2020/1/main.go b/2020/1/main.go new file mode 100644 index 0000000..88ef4ba --- /dev/null +++ b/2020/1/main.go @@ -0,0 +1,32 @@ +package main + +import ( + "fmt" + + "github.com/alexg-axis/advent-of-code/utils/go/parsing" +) + +func main() { + input, err := parsing.ReadInput() + if err != nil { + panic(err) + } + + numbers, err := input.Ints() + if err != nil { + panic(err) + } + + fmt.Println(solve(numbers)) +} + +func solve(numbers []int) int { + for i, a := range numbers { + for j, b := range numbers { + if i != j && a+b == 2020 { + return a * b + } + } + } + return -1 +} diff --git a/2020/1/main.py b/2020/1/main.py new file mode 100644 index 0000000..7db725c --- /dev/null +++ b/2020/1/main.py @@ -0,0 +1,13 @@ +from aoc import input + +def solve(numbers: list[int]) -> int | None: + for i in range(len(numbers)): + for j in range(len(numbers)): + if i != j and numbers[i] + numbers[j] == 2020: + return numbers[i] * numbers[j] + +def main(): + print(solve(input.ints)) + +if __name__ == "__main__": + main() diff --git a/2020/1/main.ts b/2020/1/main.ts new file mode 100644 index 0000000..7f14f14 --- /dev/null +++ b/2020/1/main.ts @@ -0,0 +1,12 @@ +import input from "../../utils/deno/input.ts" + +function solve(numbers: number[]): number | undefined { + for (let i = 0; i < numbers.length; i++) { + for (let j = 0; j < numbers.length; j++) { + if (i != j && numbers[i] + numbers[j] === 2020) + return numbers[i] * numbers[j] + } + } +} + +console.log(solve(input.numbers)) diff --git a/README.md b/README.md index aa7771b..3643d0b 100644 --- a/README.md +++ b/README.md @@ -28,3 +28,5 @@ The structure is generic enough, but built for macOS (although that specific log * To initialize a specific puzzle, run `AOC_YEAR=2020 AOC_MONTH=12 AOC_DAY=24 make init` 4. To run today's puzzle run `make run` * To run a specific puzzle, run `AOC_YEAR=2020 AOC_MONTH=12 AOC_DAY=24 make run` + +An example using multiple languages can be found in `2020/1`.