feat(geektime_algo): add 05_array for rust

Author: Caitlin Gao

rust/05_array/main.rs

@@ -0,0 +1,72 @@
+struct NewArray {
+    array: Vec<i32>,
+    count: i32,
+}
+
+impl NewArray {
+    fn new(capacity: usize) -> NewArray {
+        NewArray { array: Vec::with_capacity(capacity), count: 0 }
+    }
+
+    fn find(&self, index: usize) -> i32 {
+        if index > self.count as usize { return -1; }
+        self.array[index]
+    }
+
+    fn insert(&mut self, index: usize, value: i32) -> bool {
+        let array_count = self.count as usize;
+        if index > array_count || array_count == self.array.capacity() { return false; }
+
+        if index == array_count {
+            self.array.push(value);
+        } else {
+            let tmp_arr = self.array.clone();
+
+            self.array = Vec::with_capacity(self.array.capacity());
+            for i in 0..index {
+                self.array.push(tmp_arr[i]);
+            }
+
+            self.array.push(value);
+            for i in index..array_count {
+                self.array.push(tmp_arr[i]);
+            }
+        }
+
+        self.count += 1;
+        true
+    }
+
+    fn remove(&mut self, index: usize) -> i32 {
+        if index >= self.count as usize { return -1; }
+
+        let result = self.array[index];
+        let tmp_arr = self.array.clone();
+
+        self.array = Vec::with_capacity(self.array.capacity());
+        for i in 0..index {
+            self.array.push(tmp_arr[i]);
+        }
+
+        for i in index+1..self.count as usize {
+            self.array.push(tmp_arr[i]);
+        }
+
+        self.count -=1;
+        result
+    }
+}
+
+fn main() {
+    let mut new_array = NewArray::new(10);
+    assert_eq!(new_array.insert(0, 3), true);
+    assert_eq!(new_array.insert(1, 2), true);
+    assert_eq!(new_array.insert(2, 8), true);
+    assert_eq!(new_array.insert(0, 9), true);
+    assert_eq!(new_array.insert(5, 7), false);
+    assert_eq!(new_array.insert(4, 5), true);
+    assert_eq!(new_array.find(3), 8);
+    assert_eq!(new_array.find(12), -1);
+    assert_eq!(new_array.remove(1), 3);
+    assert_eq!(new_array.remove(9), -1);
+}