add: 字符串中的额外字符

.vscode/settings.json

@@ -68,6 +68,7 @@
     "lcci",
     "lcov",
     "leetcode",
+    "leetscode",
     "maxfreq",
     "maxnum",
     "minnum",
@@ -90,6 +91,7 @@
     "RUSTDOCFLAGS",
     "RUSTFLAGS",
     "rustup",
+    "sayhelloworld",
     "strs",
     "subarray",
     "subarrays",

README.md

@@ -441,6 +441,10 @@ Rust标准库`std::collections`提供了4种通用容器类型，包含一下8
 
 ### 树
 
+- [字符串中的额外字符](src/tree/extra_characters_in_a_string.rs)  [字典树, 数组, 哈希表, 字符串, 动态规划]
+
+  - LeetCode 2707. 字符串中的额外字符 <https://leetcode.cn/problems/extra-characters-in-a-string>
+
 - [从二叉搜索树到更大和树](src/tree/binary_search_tree_to_greater_sum_tree.rs)  [树, 深度优先搜索, 二叉搜索树, 二叉树]
 
   - LeetCode 1038. 从二叉搜索树到更大和树 <https://leetcode.cn/problems/binary-search-tree-to-greater-sum-tree>

src/tree/extra_characters_in_a_string.rs

@@ -0,0 +1,32 @@
+use std::collections::HashMap;
+// 字符串中的额外字符
+// https://leetcode.cn/problems/extra-characters-in-a-string
+// INLINE  ../../images/tree/extra_characters_in_a_string.jpeg
+
+pub struct Solution;
+
+impl Solution {
+    pub fn min_extra_char(s: String, dictionary: Vec<String>) -> i32 {
+        let n = s.len();
+        let mut d = vec![std::i32::MAX; n + 1];
+        let mut mp: HashMap<String, i32> = HashMap::new();
+
+        for word in dictionary {
+            *mp.entry(word).or_insert(0) += 1;
+        }
+
+        d[0] = 0;
+
+        for i in 1..=n {
+            d[i] = d[i - 1] + 1;
+
+            for j in (0..i).rev() {
+                if mp.contains_key(&s[j..i]) {
+                    d[i] = d[i].min(d[j]);
+                }
+            }
+        }
+
+        d[n]
+    }
+}

src/tree/mod.rs

@@ -12,3 +12,4 @@ pub mod maximum_sum_bst_in_binary_tree;
 pub mod time_needed_to_inform_all_employees;
 pub mod kth_ancestor_of_a_tree_node;
 pub mod binary_search_tree_to_greater_sum_tree;
+pub mod extra_characters_in_a_string;

tests/tree/extra_characters_in_a_string_test.rs

@@ -0,0 +1,24 @@
+use rust_practice::tree::extra_characters_in_a_string::Solution;
+
+#[test]
+fn min_extra_char() {
+    // 示例 1：
+    // 输入：s = "leetscode", dictionary = ["leet","code","leetcode"]
+    // 输出：1
+    // 解释：将 s 分成两个子字符串：下标从 0 到 3 的 "leet" 和下标从 5 到 8 的 "code" 。只有 1 个字符没有使用（下标为 4），所以我们返回 1 。
+    let s = "leetscode".to_string();
+    let dictionary = vec![
+        "leet".to_string(),
+        "code".to_string(),
+        "leetcode".to_string(),
+    ];
+    assert_eq!(Solution::min_extra_char(s, dictionary), 1);
+
+    // 示例 2：
+    // 输入：s = "sayhelloworld", dictionary = ["hello","world"]
+    // 输出：3
+    // 解释：将 s 分成两个子字符串：下标从 3 到 7 的 "hello" 和下标从 8 到 12 的 "world" 。下标为 0 ，1 和 2 的字符没有使用，所以我们返回 3 。
+    let s = "sayhelloworld".to_string();
+    let dictionary = vec!["hello".to_string(), "world".to_string()];
+    assert_eq!(Solution::min_extra_char(s, dictionary), 3);
+}

tests/tree/mod.rs

@@ -12,3 +12,4 @@ pub mod insufficient_nodes_in_root_to_leaf_paths_test;
 pub mod delete_nodes_and_return_forest_test;
 pub mod kth_ancestor_of_a_tree_node_test;
 pub mod binary_search_tree_to_greater_sum_tree_test;
+pub mod extra_characters_in_a_string_test;