feat: add solutions to lc problem: No.0509

YangFong · YangFong · commit afab65558c91 · 2022-03-04T10:24:58.000+08:00
No.0509.Fibonacci Number
diff --git a/solution/0500-0599/0509.Fibonacci Number/README.md b/solution/0500-0599/0509.Fibonacci Number/README.md
@@ -134,6 +134,56 @@ var fib = function (n) {
 };
 ```
 
+### **TypeScript**
+
+```ts
+function fib(n: number): number {
+    let a = 0;
+    let b = 1
+    for (let i = 0; i < n; i++) {
+        [a, b] = [b, a + b]
+    }
+    return a
+};
+```
+
+```ts
+function fib(n: number): number {
+    if (n < 2) {
+        return n;
+    }
+    return fib(n - 1) + fib(n - 2)
+};
+```
+
+### **Rust**
+
+```rust
+impl Solution {
+    pub fn fib(n: i32) -> i32 {
+        let mut a = 0;
+        let mut b = 1;
+        for _ in 0..n {
+            let t = b;
+            b = a + b;
+            a = t
+        }
+        a
+    }
+}
+```
+
+```rust
+impl Solution {
+    pub fn fib(n: i32) -> i32 {
+        if n < 2 {
+            return n;
+        }
+        Self::fib(n - 1) + Self::fib(n - 2)
+    }
+}
+```
+
 ### **...**
 
 ```
diff --git a/solution/0500-0599/0509.Fibonacci Number/README_EN.md b/solution/0500-0599/0509.Fibonacci Number/README_EN.md
@@ -124,6 +124,56 @@ var fib = function (n) {
 };
 ```
 
+### **TypeScript**
+
+```ts
+function fib(n: number): number {
+    let a = 0;
+    let b = 1
+    for (let i = 0; i < n; i++) {
+        [a, b] = [b, a + b]
+    }
+    return a
+};
+```
+
+```ts
+function fib(n: number): number {
+    if (n < 2) {
+        return n;
+    }
+    return fib(n - 1) + fib(n - 2)
+};
+```
+
+### **Rust**
+
+```rust
+impl Solution {
+    pub fn fib(n: i32) -> i32 {
+        let mut a = 0;
+        let mut b = 1;
+        for _ in 0..n {
+            let t = b;
+            b = a + b;
+            a = t
+        }
+        a
+    }
+}
+```
+
+```rust
+impl Solution {
+    pub fn fib(n: i32) -> i32 {
+        if n < 2 {
+            return n;
+        }
+        Self::fib(n - 1) + Self::fib(n - 2)
+    }
+}
+```
+
 ### **...**
 
 ```
diff --git a/solution/0500-0599/0509.Fibonacci Number/Solution.rs b/solution/0500-0599/0509.Fibonacci Number/Solution.rs
@@ -0,0 +1,12 @@
+impl Solution {
+    pub fn fib(n: i32) -> i32 {
+        let mut a = 0;
+        let mut b = 1;
+        for _ in 0..n {
+            let t = b;
+            b = a + b;
+            a = t
+        }
+        a
+    }
+}
diff --git a/solution/0500-0599/0509.Fibonacci Number/Solution.ts b/solution/0500-0599/0509.Fibonacci Number/Solution.ts
@@ -0,0 +1,8 @@
+function fib(n: number): number {
+    let a = 0;
+    let b = 1;
+    for (let i = 0; i < n; i++) {
+        [a, b] = [a, a + b];
+    }
+    return a;
+}
