Wrote program for Day 25

README.md

@@ -71,7 +71,7 @@ We encourage you to share your progress and ask questions in the Discussions sec
 | Day #22       | [Marcio Mellos Challenge](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-22_Marcio-Mellos-Challenge)               | :white_check_mark:      |
 | Day #23       | [The Dining Philosophers](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-23_The-Dining_Philosophers)               | :white_check_mark:      |
 | Day #24       | [The Josephus Problem](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-24_The-Josephus-Problem)                  | :white_check_mark:      |
-| Day #25       | [Coin Trouble](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-25_Coin-Trouble)                          | :white_large_square:      |
+| Day #25       | [Coin Trouble](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-25_Coin-Trouble)                          | :white_check_mark:      |
 | Day #26       | [Briefcase Lock](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-26_Briefcase-Lock)                        | :white_large_square:      |
 | Day #27       | [Task Scheduler](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-27_Task-Scheduler)                        | :white_large_square:      |
 | Day #28       | [Word Search](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-28_Word-Search)                           | :white_large_square:      |

Week-04/Day-25_Coin-Trouble/day25/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "day25"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

Week-04/Day-25_Coin-Trouble/day25/src/lib.rs

@@ -0,0 +1,35 @@
+pub fn coins_div(coins: &[usize]) -> bool {
+    let sum: usize = coins.iter().copied().sum();
+    let each = sum / 3;
+
+    if sum % 3 != 0 {
+        false
+    } else {
+        try_coins_div(coins, 0, each)
+    }
+}
+
+fn try_coins_div(coins: &[usize], current_coins: usize, should_have: usize) -> bool {
+    if coins.is_empty() {
+        return current_coins == 0;
+    }
+
+    for (i, c) in coins.iter().enumerate() {
+        let coins_without_current = [&coins[..i], &coins[i + 1..]].concat();
+        if current_coins + c <= should_have
+            && try_coins_div(
+                &coins_without_current,
+                if current_coins + c == should_have {
+                    0
+                } else {
+                    current_coins + c
+                },
+                should_have,
+            )
+        {
+            return true;
+        }
+    }
+
+    false
+}

Week-04/Day-25_Coin-Trouble/day25/src/main.rs

@@ -0,0 +1,25 @@
+use std::io::{self, Write};
+
+use day25::coins_div;
+
+fn main() {
+    let mut buffer = String::new();
+
+    print!("Insert the value of the coins space separated: ");
+    io::stdout().flush().expect("Failed to flush stdout");
+
+    io::stdin()
+        .read_line(&mut buffer)
+        .expect("Failed to read line");
+
+    let coins: Vec<usize> = buffer
+        .split_whitespace()
+        .map(|x| x.parse().expect("Input must be made of numbers"))
+        .collect();
+
+    if coins_div(&coins) {
+        println!("The coins can be divided equally")
+    } else {
+        println!("The coins can't be divided equally");
+    }
+}

Week-04/Day-25_Coin-Trouble/day25/tests/examples.rs

@@ -0,0 +1,18 @@
+#[cfg(test)]
+mod examples {
+    use day25::coins_div;
+
+    #[test]
+    fn example1() {
+        assert!(coins_div(&[1, 2, 3, 2, 2, 2, 3]));
+    }
+
+    #[test]
+    fn example2() {
+        assert!(!coins_div(&[5, 3, 10, 1, 2]));
+    }
+    #[test]
+    fn example3() {
+        assert!(coins_div(&[2, 4, 3, 2, 4, 9, 7, 8, 6, 9]));
+    }
+}