Merge pull request #59 from tony84727/leetcode/76

feat: leetcode/76

Author: tony84727

src/leetcode/algorithm_76/README.md

@@ -0,0 +1,3 @@
+Minimum Window Substring
+========================
+[leetcode](https://leetcode.com/problems/minimum-window-substring/)

src/leetcode/algorithm_76/mod.rs

@@ -0,0 +1,25 @@
+pub mod sliding_window;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use test::Bencher;
+    use test_case::test_case;
+
+    #[test_case("ADOBECODEBANC", "ABC", "BANC"; "example 1")]
+    #[test_case("a", "aa", ""; "case 1")]
+    #[test_case("a", "a", "a"; "case 2")]
+    fn test_sliding_window_solution(s: &str, t: &str, expected: &str) {
+        assert_eq!(
+            expected.to_string(),
+            sliding_window::Solution::min_window(s.to_string(), t.to_string())
+        );
+    }
+
+    #[bench]
+    fn bench_sliding_window_example_1(b: &mut Bencher) {
+        b.iter(|| {
+            sliding_window::Solution::min_window("ADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANCADOBECODEBANC".to_string(), "ABC".to_string());
+        })
+    }
+}

src/leetcode/algorithm_76/sliding_window.rs

@@ -0,0 +1,85 @@
+use std::collections::HashMap;
+
+pub struct Solution;
+
+struct Scanning {
+    to_find: HashMap<char, i32>,
+    missing: u32,
+}
+
+impl Scanning {
+    fn new(target: String) -> Self {
+        let mut to_find = HashMap::<char, i32>::new();
+        for c in target.chars() {
+            *to_find.entry(c).or_default() += 1;
+        }
+        let missing = to_find.len() as u32;
+        Self { to_find, missing }
+    }
+    fn meet(&mut self, c: char) {
+        match self.to_find.get_mut(&c) {
+            Some(count) => {
+                if *count == 1 {
+                    self.missing -= 1;
+                }
+                *count -= 1;
+            }
+            None => (),
+        }
+    }
+
+    fn remove(&mut self, c: char) {
+        match self.to_find.get_mut(&c) {
+            Some(count) => {
+                if *count == 0 {
+                    self.missing += 1;
+                }
+                *count += 1;
+            }
+            None => (),
+        }
+    }
+
+    fn is_satisfied(&self) -> bool {
+        self.missing == 0
+    }
+
+    fn is_important(&self, c: char) -> bool {
+        self.to_find.contains_key(&c)
+    }
+}
+
+impl Solution {
+    pub fn min_window(s: String, t: String) -> String {
+        let mut scanning = Scanning::new(t);
+        let mut left = 0;
+        let mut answer: Option<&[char]> = None;
+        let s: Vec<char> = s.chars().collect();
+        for (right, &new) in s.iter().enumerate() {
+            if scanning.is_important(new) {
+                scanning.meet(new);
+                if scanning.is_satisfied() {
+                    for current_left in left..=right {
+                        if scanning.is_important(s[current_left]) {
+                            scanning.remove(s[current_left]);
+                            if !scanning.is_satisfied() {
+                                match answer {
+                                    Some(current) if right - current_left < current.len() => {
+                                        answer = Some(&s[current_left..=right]);
+                                    }
+                                    None => {
+                                        answer = Some(&s[current_left..=right]);
+                                    }
+                                    _ => (),
+                                }
+                                left = current_left + 1;
+                                break;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        answer.unwrap_or_default().iter().collect()
+    }
+}

src/leetcode/mod.rs

@@ -1,3 +1,4 @@
+pub mod algorithm_76;
 pub mod algorithm_79;
 pub mod algorithm_73;
 pub mod add_two_numbers_2;