方法总结
A* 算法计算步骤
1. 初始化:
Open list = {start}
g(start) = 0
f(start) = g(start) + h(start)
2. 循环:
a. 从 Open list 选取 f 值最小的节点 n
b. 将 n 从 Open list 移到 Closed list
c. 如果是目标节点,停止并回溯路径
d. 对 n 的每个邻居 m:
- tentative_g = g(n) + distance(n, m)
- 若 m 在 Closed list 中,跳过
- 若 m 不在 Open list 中或 tentative_g < g(m):
更新 g(m) = tentative_g
更新 f(m) = g(m) + h(m)
设置 parent(m) = n
将 m 加入 Open list(若不在)
表格填写模板
| Node | g(n) | h(n) | f(n) | Parent |
|---|---|---|---|---|
| S | 0 | 5 | 5 | - |
| A | 2 | 3 | 5 | S |
| B | 4 | 4 | 8 | A |
关键公式
Dijkstra 算法计算步骤
1. 初始化:
dist[start] = 0
dist[其他节点] = ∞
visited = {}
2. 循环直到 visited 包含所有节点:
a. 选取未访问节点中 dist 最小的节点 u
b. 将 u 加入 visited
c. 对 u 的每个邻居 v:
如果 dist[u] + weight(u, v) < dist[v]:
更新 dist[v] = dist[u] + weight(u, v)
prev[v] = u
表格填写模板
| Iteration | Current | A | B | C | D | E |
|---|---|---|---|---|---|---|
| 0 | - | 0 | ∞ | ∞ | ∞ | ∞ |
| 1 | A | - | 4 | 2 | ∞ | ∞ |
| 2 | C | - | 3 | - | 5 | ∞ |
| 3 | B | - | - | - | 5 | 8 |
机器学习四分类识别方法
| 特征/线索词 | 类型 |
|---|---|
| "labelled data", "known output", "classified", "training set with correct answers" | Supervised |
| "unlabelled data", "find patterns", "group", "cluster", "no target output" | Unsupervised |
| "agent", "environment", "reward", "punishment", "trial and error", "game" | Reinforcement |
| "multiple hidden layers", "deep neural network", "automatic feature extraction" | Deep Learning |
ANN 结构速记
Input Layer (features)
↓
Hidden Layer(s) — weighted sum → activation function → output
↓
Output Layer (prediction)
↓
Error calculation → Back propagation → Weight update