add solutions for patterns.md

solutions/pattern-match/patterns.md

@@ -0,0 +1,88 @@
+1.
+```rust
+fn main() {}
+fn match_number(n: i32) {
+    match n {
+        // match a single value
+        1 => println!("One!"),
+        // fill in the blank with `|`, DON'T use `..` ofr `..=`
+        2 | 3 | 4 | 5 => println!("match 2 -> 5"),
+        // match an inclusive range
+        6..=10 => {
+            println!("match 6 -> 10")
+        },
+        _ => {
+            println!("match 11 -> +infinite")
+        }
+    }
+}
+```
+
+2.
+```rust
+
+struct Point {
+    x: i32,
+    y: i32,
+}
+
+fn main() {
+    // fill in the blank to let p match the second arm
+    let p = Point { x: 2, y: 20 }; // x can be [0, 5], y can be 10 20 or 30
+
+    match p {
+        Point { x, y: 0 } => println!("On the x axis at {}", x),
+        // second arm
+        Point { x: 0..=5, y: y@ (10 | 20 | 30) } => println!("On the y axis at {}", y),
+        Point { x, y } => println!("On neither axis: ({}, {})", x, y),
+    }
+}
+```
+
+3.
+```rust
+enum Message {
+    Hello { id: i32 },
+}
+
+fn main() {
+    let msg = Message::Hello { id: 5 };
+
+    match msg {
+        Message::Hello {
+            id:  id@3..=7,
+        } => println!("Found an id in range [3, 7]: {}", id),
+        Message::Hello { id: newid@(10 | 11 | 12) } => {
+            println!("Found an id in another range [10, 12]: {}", newid)
+        }
+        Message::Hello { id } => println!("Found some other id: {}", id),
+    }
+}
+```
+
+4.
+```rust
+fn main() {
+    let num = Some(4);
+    let split = 5;
+    match num {
+        Some(x) if x < split => assert!(x < split),
+        Some(x) => assert!(x >= split),
+        None => (),
+    }
+}
+```
+
+5.
+```rust
+fn main() {
+    let numbers = (2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048);
+
+    match numbers {
+        (first,..,last) => {
+           assert_eq!(first, 2);
+           assert_eq!(last, 2048);
+        }
+    }
+}
+```