-[752. Open the Lock](en/1-1000/752-open-the-lock.md) was solved in_Python_ and 2 ways.

-[433. Minimum Genetic Mutation](en/1-1000/433-minimum-genetic-mutation.md) was solved in_Python_.

-[433. Minimum Genetic Mutation](en/1-1000/433-minimum-genetic-mutation.md) was solved in_Python_ and 2 ways.

More LeetCode problems will be added soon.

**Breadth-First Search** treats each vertex equally, which inevitably leads to poor performance.

**A-Star Algorithm** calculates the**distance** between each`vertex` and the`target vertex`, and prioritizes vertices withclose distances, whichgreatly improvesperformance.

The`A* (A-Star) algorithm` calculates the**distance** between each`vertex` and the`target vertex`, and**prioritizes vertices withcloser distances**, whichis equivalent to indicating which vertex to process next, so theperformance is greatly improved!

1. Use`priority_queue`.

2. The function for calculating`distance` should be**carefully designed** (poor design will lead to**subtle** errors in the results).

3. In special cases, simply using`distance` as the sorting basisfor`priority_queue` is not enough, andyou needto**make some adjustments**, such as adding it to the`step_count` variable value(not involved in this example).

3. In special cases, simply using`distance` as the sorting basisof`priority_queue` is not enough, andit is also necessaryto**adjust** (for example, add it to the`number of steps` variable value) to make the last few steps accurate(not involved in this example, yet in this one[1197. Minimum Knight Moves](https://leetcode.com/problems/minimum-knight-moves/)).

`广度优先搜索` 对每一个顶点都同等对待，这样难免性能会差。

`A* (A-Star) 算法` 会对每一个`顶点`与`目标顶点`的**距离**进行计算，**距离近的顶点优先处理**，性能提升会很大。

`A* (A-Star) 算法` 会对每一个`顶点`与`目标顶点`的**距离**进行计算，**距离近的顶点优先处理**，相当于为下一步处理哪个顶点指明了方向，因此性能有很大的提升！

1. 要用`priority_queue`。

2. 计算距离的函数要**精心设计**。设计不好，将导致不易察觉的结果错误!

3. 在特殊情况下，单纯地用`距离`作为`priority_queue`的排序依据还不够，还要**调整一下**，比如与`步数`变量值相加（本例子不涉及）。

3. 在特殊情况下，单纯地用`距离`作为`priority_queue`的排序依据还不够，还要**调整一下**（比如与`步数`变量值相加），以使最后几步能精确（本例子不涉及，但这个例子[1197. Minimum Knight Moves](https://leetcode.com/problems/minimum-knight-moves/) 涉及）。