Merge branch 'master' of github.com:jinbudaily/leetcode-master

合并远程代码

problems/0123.买卖股票的最佳时机III.md

@@ -413,7 +413,52 @@ function maxProfit(prices: number[]): number {
 };
 ```
 
+Rust：
 
+> 版本一
+
+```rust
+impl Solution {
+    pub fn max_profit(prices: Vec<i32>) -> i32 {
+        /*
+         * 定义 5 种状态:
+         * 0: 没有操作, 1: 第一次买入, 2: 第一次卖出, 3: 第二次买入, 4: 第二次卖出
+         */
+        let mut dp = vec![vec![0; 5]; prices.len()];
+        dp[0][1] = -prices[0];
+        dp[0][3] = -prices[0];
+
+        for (i, &p) in prices.iter().enumerate().skip(1) {
+            // 不操作
+            // dp[i][0] = dp[i - 1][0];
+            dp[i][1] = dp[i - 1][1].max(-p);
+            dp[i][2] = dp[i - 1][2].max(dp[i - 1][1] + p);
+            dp[i][3] = dp[i - 1][3].max(dp[i - 1][2] - p);
+            dp[i][4] = dp[i - 1][4].max(dp[i - 1][3] + p);
+        }
+
+        dp[prices.len() - 1][4]
+    }
+}
+```
+
+> 版本二（绕）
+
+```rust
+impl Solution {
+    pub fn max_profit(prices: Vec<i32>) -> i32 {
+        let (mut one_buy, mut one_sale, mut two_buy, mut two_sale) = (-prices[0], 0, -prices[0], 0);
+
+        for p in prices {
+            one_buy = one_buy.max(-p);
+            one_sale = one_sale.max(p + one_buy);
+            two_buy = two_buy.max(one_sale - p);
+            two_sale = two_sale.max(two_buy + p);
+        }
+        two_sale
+    }    
+}
+```
 
 
 <p align="center">

problems/0188.买卖股票的最佳时机IV.md

@@ -474,6 +474,55 @@ function maxProfit(k: number, prices: number[]): number {
 };
 ```
 
+Rust：
+
+```rust
+impl Solution {
+    pub fn max_profit(k: i32, prices: Vec<i32>) -> i32 {
+        let mut dp = vec![vec![0; 2 * k as usize + 1]; prices.len()];
+
+        for v in dp[0].iter_mut().skip(1).step_by(2) {
+            *v = -prices[0];
+        }
+
+        for (i, &p) in prices.iter().enumerate().skip(1) {
+            for j in (0..2 * k as usize - 1).step_by(2) {
+                dp[i][j + 1] = dp[i - 1][j + 1].max(dp[i - 1][j] - p);
+                dp[i][j + 2] = dp[i - 1][j + 2].max(dp[i - 1][j + 1] + p);
+            }
+        }
+
+        dp[prices.len() - 1][2 * k as usize]
+    }
+}
+```
+
+空间优化：
+
+```rust
+impl Solution {
+    pub fn max_profit(k: i32, prices: Vec<i32>) -> i32 {
+        let mut dp = vec![0; 2 * k as usize + 1];
+        for v in dp.iter_mut().skip(1).step_by(2) {
+            *v = -prices[0];
+        }
+
+        for p in prices {
+            for i in 1..=2 * k as usize {
+                if i % 2 == 1 {
+                    // 买入
+                    dp[i] = dp[i].max(dp[i - 1] - p);
+                    continue;
+                }
+                // 卖出
+                dp[i] = dp[i].max(dp[i - 1] + p);
+            }
+        }
+
+        dp[2 * k as usize]
+    }
+}
+```
 
 
 <p align="center">