day02: rust

02/.gitignore

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+day02

02/README.md

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+# [Day 2](https://adventofcode.com/2023/day/2) 
+:gift::gift:
+
+Today's language: **Rust**
+
+My very first rust program!
+
+```shell
+rustc day02.rs
+./day02
+```

02/day02.rs

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+use std::io::{self, BufRead};
+
+fn main() {
+    let max_red:    u32 = 12;
+    let max_green:  u32 = 13;
+    let max_blue:   u32 = 14;
+
+    let lines = read_lines("input.txt");
+    let mut sum_ind_possible: u32 = 0;
+    let mut sum_ind_minpower: u32 = 0;
+    for line in lines {
+        let mut game_possible = true;
+        let Ok(game) = line else { panic!("Line not ok"); };
+        let Some(colon) = game.find(':') else { panic!("Could not find ':'"); };
+        let game_index = &game[5..colon].parse::<u32>().unwrap();
+        let mut red = 0;
+        let mut green = 0;
+        let mut blue = 0;
+        for samples in game[colon+2..].split("; ") {
+            for color_value in samples.split(", ") {
+                let mut iter = color_value.split(' ');
+                let count; 
+                if let Some(c) = iter.next() { count = c.parse::<u32>().unwrap(); } else { panic!("Invalid line: {}", game); };
+                let Some(color) = iter.next() else { panic!("Invalid line: {}", game); };
+                // println!("Color={}, value={}", color, count);
+                let do_color = |value: u32, colorvalue: &mut u32, max_color: u32| {
+                    if value > *colorvalue {
+                        *colorvalue = value;
+                    }
+                    return value <= max_color;
+                };
+                game_possible &= match color {
+                    "red"   => do_color(count, &mut red, max_red),
+                    "green" => do_color(count, &mut green, max_green),
+                    "blue"  => do_color(count, &mut blue, max_blue),
+                    _ => false,
+                };
+            }
+        }
+        if game_possible { sum_ind_possible += game_index };
+        sum_ind_minpower += red * green * blue;
+    }
+    println!("Sum of indices of possible games: {}", sum_ind_possible);
+    println!("Sum of power of minimum sets: {}", sum_ind_minpower);
+}
+
+// fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<std::fs::File>>>
+// where P: AsRef<std::path::Path>, {
+//     let file = std::fs::File::open(filename)?;
+//     Ok(std::io::BufReader::new(file).lines())
+// }
+
+fn read_lines<P>(filename: P) -> io::Lines<io::BufReader<std::fs::File>>
+where P: AsRef<std::path::Path>, {
+    return match std::fs::File::open(filename) {
+        Err(why) => panic!("Could not open file. {}", why),
+        Ok(file) => std::io::BufReader::new(file).lines()
+    };
+}
+