3573. 买卖股票的最佳时机 V

src/main.rs

@@ -1,30 +1,31 @@
-use std::collections::HashMap;
-
 struct Solution;
 mod arr;
 impl Solution {
-    pub fn special_triplets(nums: Vec<i32>) -> i32 {
-        let mut map: HashMap<i32, i32> = HashMap::new();
-        let mut map2: HashMap<i32, i32> = HashMap::new();
-        let md = 1e9 as i64 + 7;
-        let mut ans = 0_i64;
-        nums.iter().for_each(|x| {
-            map.insert(*x, map.get(&x).copied().unwrap_or(0) + 1);
-        });
-        map2.insert(nums[0], 1);
-        for i in 1..nums.len() - 1 {
-            let mp2d = map2.get(&(nums[i] * 2)).copied().unwrap_or(0) as i64;
-            let mut mp1d = map.get(&(nums[i] * 2)).copied().unwrap_or(0) as i64 - mp2d;
-            if nums[i] == nums[i] * 2 {
-                mp1d -= 1;
-            }
-            ans = (ans + mp1d * mp2d) % md;
-            map2.insert(nums[i], map2.get(&nums[i]).copied().unwrap_or(0) + 1);
+    pub fn maximum_profit(prices: Vec<i32>, k: i32) -> i64 {
+        let k = k as usize;
+        // 0 无 1 持有 2 做空
+        let mut dp = vec![vec![vec![-0x3f3f3f3f_i64;3];k + 1]; prices.len()];
+        dp[0][0][0] = 0;
+        for i in 1..=k {
+            dp[0][i][0] = 0;
+            dp[0][i][1] = -prices[0] as i64;
+            dp[0][i][2] = prices[0] as i64;
         }
-        ans as i32
+        for i in 1..prices.len() {
+            dp[i][0][1] = dp[i-1][0][1];
+            dp[i][0][2] = dp[i-1][0][2];
+            dp[i][0][0] = dp[i-1][0][0].max(dp[i-1][0][1] + prices[i] as i64).max(dp[i-1][0][2] - prices[i] as i64);
+            for j in 1..=k {
+                dp[i][j][0] = dp[i-1][j][0].max(dp[i-1][j][1] + prices[i] as i64).max(dp[i-1][j][2] - prices[i] as i64);
+                dp[i][j][1] = dp[i-1][j][1].max(dp[i-1][j-1][0] - prices[i] as i64);
+                dp[i][j][2] = dp[i-1][j][2].max(dp[i-1][j-1][0] + prices[i] as i64);
+            }
+        }
+        println!("{:?}",dp);
+        dp.last().unwrap().last().unwrap()[0]
     }
 }
 fn main() {
-    let result = Solution::special_triplets(vec![0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]);
+    let result = Solution::maximum_profit(vec![5,10,9], 1);
     println!("{:?}", result);
 }