Wrote program for Day 16

README.md

@@ -62,7 +62,7 @@ We encourage you to share your progress and ask questions in the Discussions sec
 | Day #13       | [Need Help With Your Packing](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-02/Day-13_Need-Help-With-Packing)           | :white_check_mark:      |
 | Day #14       | [The Karacas Encryption Algorithm](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-02/Day-14_Karacas-Encryption-Algorithm)      | :white_check_mark:      |
 | Day #15       | [Valid Anagram](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-03/Day-15_Valid-Anagram)                         | :white_check_mark:      |
-| Day #16       | [Nim Game](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-03/Day-16_Nim-Game)                              | :white_large_square:      |
+| Day #16       | [Nim Game](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-03/Day-16_Nim-Game)                              | :white_check_mark:      |
 | Day #17       | [Prison Break](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-03/Day-17_Prison-Break)                          | :white_large_square:      |
 | Day #18       | [Unique Paths](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-03/Day-18_Unique-Paths)                          | :white_large_square:      |
 | Day #19       | [URL Shortener](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-03/Day-19_URL-Shortener)                         | :white_large_square:      |

Week-03/Day-16_Nim-Game/day16/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "day16"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

Week-03/Day-16_Nim-Game/day16/src/lib.rs

@@ -0,0 +1,28 @@
+use std::collections::HashMap;
+
+pub fn nim_winner(n: usize) -> bool {
+    let mut memo: HashMap<usize, HashMap<bool, bool>> = HashMap::new();
+    nim_dp(n, true, &mut memo)
+}
+
+pub fn nim_dp(moves: usize, turn: bool, memo: &mut HashMap<usize, HashMap<bool, bool>>) -> bool {
+    if moves <= 3 {
+        return turn;
+    }
+
+    if memo.contains_key(&moves) && memo[&moves].contains_key(&turn) {
+        return memo[&moves][&turn];
+    }
+
+    memo.insert(moves, HashMap::new());
+
+    for i in 1..=3 {
+        if nim_dp(moves - i, !turn, memo) {
+            memo.get_mut(&moves).unwrap().insert(turn, true);
+            return true;
+        }
+    }
+
+    memo.get_mut(&moves).unwrap().insert(turn, false);
+    false
+}

Week-03/Day-16_Nim-Game/day16/src/main.rs

@@ -0,0 +1,25 @@
+use std::io::{self, Write};
+
+use day16::nim_winner;
+
+fn main() {
+    let mut buffer = String::new();
+
+    print!("How many stones will you have during your turn? ");
+    io::stdout().flush().expect("Failed to flush stdout.");
+
+    io::stdin()
+        .read_line(&mut buffer)
+        .expect("Failed to read from stdin");
+
+    let stones = buffer
+        .trim()
+        .parse()
+        .expect("Your input is not a valid number");
+
+    if nim_winner(stones) {
+        println!("You will win!");
+    } else {
+        println!("You will lose!");
+    }
+}

Week-03/Day-16_Nim-Game/day16/tests/examples.rs

@@ -0,0 +1,16 @@
+use day16::nim_winner;
+
+#[test]
+fn example1() {
+    assert!(!nim_winner(4));
+}
+
+#[test]
+fn example2() {
+    assert!(nim_winner(1));
+}
+
+#[test]
+fn example3() {
+    assert!(nim_winner(2));
+}