From e99d23690e8fcb41ff92c807252b7499539a4390 Mon Sep 17 00:00:00 2001
From: xblakicex <xblakicex@outlook.com>
Date: Fri, 13 Jan 2023 20:41:18 +0100
Subject: [PATCH] =?UTF-8?q?=E2=9C=A8=20feat(space=5Fcomplexity):=20add=20r?=
 =?UTF-8?q?ust=20code?=
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---
 .../space_complexity.rs                       | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 codes/rust/chapter_computational_complexity/space_complexity.rs

diff --git a/codes/rust/chapter_computational_complexity/space_complexity.rs b/codes/rust/chapter_computational_complexity/space_complexity.rs
new file mode 100644
index 000000000..a65ebb748
--- /dev/null
+++ b/codes/rust/chapter_computational_complexity/space_complexity.rs
@@ -0,0 +1,70 @@
+#![allow(unused_variables)]
+/**
+ * File: space_complexity.cpp
+ * Created Time: 2023-01-13
+ * Author: xBLACICEx (xBLACKICEx@outlook.com )
+*/
+
+use std::collections::HashMap;
+
+/* 函数 */
+fn func() {
+    // do something
+}
+
+/* 常数阶 */
+fn constant(n: i32) {
+    // TODO
+}
+
+/* 线性阶 */
+fn linear(n: i32) {
+    // 长度为 n 的数组占用 O(n) 空间
+    let nums = vec![0; n as usize];
+    let map: HashMap<_, _> = (0..n).map(|i| (i, format!("{}", i))).collect();
+}
+
+/* 线性阶（递归实现） */
+fn linear_recur(n: i32) {
+    println!("递归 n = {n}");
+    if n == 1 {
+        return;
+    }
+    linear_recur(n - 1);
+}
+
+/* 平方阶 */
+fn quadratic(n: i32) {
+    // 二维列表占用 O(n^2) 空间
+    let num_matrix = vec![vec![0; n as usize]; n as usize];
+}
+
+/* 平方阶（递归实现） */
+fn quadratic_recur(n: i32) -> i32 {
+    if n <= 0 {
+        return 0
+    }
+    // 数组 nums 长度为 n, n-1, ..., 2, 1
+    let nums = vec![0; n as usize];
+    println!("递归 n = {n} 中的 nums 长度 = {}", nums.len());
+    return quadratic_recur(n - 1);
+}
+
+fn build_tree(n: usize) {
+    // TODO
+}
+
+fn main() {
+   let n = 5;
+    /* 常数阶 */
+    constant(n);
+    /* 线性阶 */
+    linear(n);
+    linear_recur(n);
+    /* 平方阶 */
+    quadratic(n);
+    quadratic_recur(n);
+    /* 指数阶 */
+    // let root = build_tree(n);
+    // print_tree(root);
+}
\ No newline at end of file