feat: add tests

Author: jtr109

Cargo.lock

@@ -48,4 +48,5 @@ members = [
     "my_calendar_i",
     "stone_game_vii",
     "minumum_number_of_refueling_stops",
+    "palindrome_pairs",
 ]

Cargo.toml

@@ -1,22 +1,38 @@
+use std::collections::BinaryHeap;
+
 pub struct Solution {}
 
 impl Solution {
     pub fn min_refuel_stops(target: i32, start_fuel: i32, stations: Vec<Vec<i32>>) -> i32 {
-        let mut furthest = vec![0; stations.len() + 1]; // furthest distance after ith refueling
-        furthest[0] = start_fuel;
-        for i in 0..stations.len() {
-            for t in 0..i + 1 {
-                if furthest[t] >= stations[i][0] {
-                    furthest[t + 1] = furthest[t + 1].max(furthest[t] + stations[i][1]);
-                }
+        /*!
+         * 解释可以查看[这个讨论](https://leetcode.com/problems/minimum-number-of-refueling-stops/discuss/294025/Java-Simple-Code-Greedy)。
+         *
+         * 主要思路：
+         *
+         * 把可以到达的最远距离中的所有站点的加油量加入优先队列备选，从中找到最大的加油量并弹出（避免重复加油），用以延长最远距离。
+         * 最远距离延长后，可以选择的加油站也就增多了。将新增的可选加油站的加油量将钻石优先队列。
+         *
+         * 循环往复直到到达目标。
+         *
+         * 如果达到某个最远距离但是已经没有可以备选的加油站了，那么说明到不了终点。
+         */
+        let mut stops = 0;
+        let mut furthest = start_fuel;
+        let mut i = 0;
+        let mut pq = BinaryHeap::new(); // 备选的加油量
+        while furthest < target {
+            while i < stations.len() && stations[i][0] <= furthest {
+                pq.push(stations[i][1]);
+                i += 1;
             }
-        }
-        for (t, d) in furthest.iter().enumerate() {
-            if *d >= target {
-                return t as i32;
+            if pq.is_empty() {
+                // 永远到不了 target
+                return -1;
             }
+            furthest += pq.pop().unwrap(); // 弹出备选的最大加油量，延长最远距离
+            stops += 1;
         }
-        -1
+        stops
     }
 }
 

minumum_number_of_refueling_stops/src/lib.rs

@@ -0,0 +1,9 @@
+[package]
+name = "palindrome_pairs"
+version = "0.1.0"
+authors = ["Ryan Li <conbas2019@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

palindrome_pairs/Cargo.toml

@@ -0,0 +1,42 @@
+pub struct Solution {}
+
+impl Solution {
+    pub fn palindrome_pairs(words: Vec<String>) -> Vec<Vec<i32>> {}
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn as_expected(words: Vec<&str>, expected: Vec<[i32; 2]>) {
+        let result = Solution::palindrome_pairs(words.iter().map(|x| x.to_string()).collect());
+        result.sort();
+        let expected_vector = expected
+            .iter()
+            .map(|x| x.to_vec())
+            .collect::<Vec<Vec<i32>>>();
+        expected_vector.sort();
+        assert_eq!(result, expected_vector);
+    }
+
+    #[test]
+    fn example_1() {
+        let words = ["abcd", "dcba", "lls", "s", "sssll"];
+        let expected = [[0, 1], [1, 0], [3, 2], [2, 4]];
+        as_expected(words.to_vec(), expected.to_vec());
+    }
+
+    #[test]
+    fn example_2() {
+        let words = ["bat", "tab", "cat"];
+        let expected = [[0, 1], [1, 0]];
+        as_expected(words.to_vec(), expected.to_vec());
+    }
+
+    #[test]
+    fn example_3() {
+        let words = ["a", ""];
+        let expected = [[0, 1], [1, 0]];
+        as_expected(words.to_vec(), expected.to_vec());
+    }
+}