feat: add solutions to lcs problems 02,03

This commit is contained in:
yanglbme 2021-09-08 17:32:41 +08:00
parent a7a22ee97d
commit d402811c9a
7 changed files with 272 additions and 5 deletions

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@ -28,7 +28,7 @@
name: 'leetcode',
logo: '/images/doocs-leetcode.png',
search: [
'/', '/solution/', '/lcof/', '/lcof2/', '/lcci/', '/lcs', 'lcp', '/basic/'
'/', '/solution/', '/lcof/', '/lcof2/', '/lcci/', '/lcs/', '/lcp/', '/basic/'
],
loadSidebar: 'summary.md',
auto2top: true,

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@ -36,6 +36,10 @@
<!-- 这里可写通用的实现逻辑 -->
统计各个问题类型出现的次数,按照次数降序排列。
然后依次选择问题类型,直至满足条件。
<!-- tabs:start -->
### **Python3**
@ -43,7 +47,18 @@
<!-- 这里可写当前语言的特殊实现逻辑 -->
```python
class Solution:
def halfQuestions(self, questions: List[int]) -> int:
counter = collections.Counter(questions)
counter = OrderedDict(counter.most_common())
n = len(questions) >> 1
res = 0
for _, v in counter.items():
res += 1
if v >= n:
return res
n -= v
return res
```
### **Java**
@ -51,7 +66,25 @@
<!-- 这里可写当前语言的特殊实现逻辑 -->
```java
class Solution {
public int halfQuestions(int[] questions) {
int[] counter = new int[1010];
for (int e : questions) {
++counter[e];
}
int n = questions.length >> 1;
Arrays.sort(counter);
int res = 0;
for (int i = counter.length - 1; i >= 0; --i) {
++res;
if (counter[i] >= n) {
return res;
}
n -= counter[i];
}
return res;
}
}
```
### **...**

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@ -0,0 +1,19 @@
class Solution {
public int halfQuestions(int[] questions) {
int[] counter = new int[1010];
for (int e : questions) {
++counter[e];
}
int n = questions.length >> 1;
Arrays.sort(counter);
int res = 0;
for (int i = counter.length - 1; i >= 0; --i) {
++res;
if (counter[i] >= n) {
return res;
}
n -= counter[i];
}
return res;
}
}

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@ -0,0 +1,12 @@
class Solution:
def halfQuestions(self, questions: List[int]) -> int:
counter = collections.Counter(questions)
counter = OrderedDict(counter.most_common())
n = len(questions) >> 1
res = 0
for _, v in counter.items():
res += 1
if v >= n:
return res
n -= v
return res

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@ -15,7 +15,7 @@
> 输出:`1`
>
> 解释4 个主题空间中,只有 1 个不与走廊相邻,面积为 1。
> ![image.png](https://pic.leetcode-cn.com/1613708145-rscctN-image.png)
> ![image.png](https://cdn.jsdelivr.net/gh/doocs/leetcode@main/lcs/LCS%2003.%20主题空间/images/1613708145-rscctN-image.png)
**示例 2:**
@ -24,7 +24,7 @@
> 输出:`3`
>
> 解释8 个主题空间中,有 5 个不与走廊相邻,面积分别为 3、1、1、1、2最大面积为 3。
> ![image.png](https://cdn.jsdelivr.net/gh/doocs/leetcode@main/lcs/LCS%2003.%20主题空间/images/613707985-KJyiXJ-image.png)
> ![image.png](https://cdn.jsdelivr.net/gh/doocs/leetcode@main/lcs/LCS%2003.%20主题空间/images/1613707985-KJyiXJ-image.png)
**提示:**
@ -36,6 +36,67 @@
<!-- 这里可写通用的实现逻辑 -->
并查集。
并查集模板:
模板 1——朴素并查集
```python
# 初始化p存储每个点的父节点
p = list(range(n))
# 返回x的祖宗节点
def find(x):
if p[x] != x:
# 路径压缩
p[x] = find(p[x])
return p[x]
# 合并a和b所在的两个集合
p[find(a)] = find(b)
```
模板 2——维护 size 的并查集:
```python
# 初始化p存储每个点的父节点size只有当节点是祖宗节点时才有意义表示祖宗节点所在集合中点的数量
p = list(range(n))
size = [1] * n
# 返回x的祖宗节点
def find(x):
if p[x] != x:
# 路径压缩
p[x] = find(p[x])
return p[x]
# 合并a和b所在的两个集合
if find(a) != find(b):
size[find(b)] += size[find(a)]
p[find(a)] = find(b)
```
模板 3——维护到祖宗节点距离的并查集
```python
# 初始化p存储每个点的父节点d[x]存储x到p[x]的距离
p = list(range(n))
d = [0] * n
# 返回x的祖宗节点
def find(x):
if p[x] != x:
t = find(p[x])
d[x] += d[p[x]]
p[x] = t
return p[x]
# 合并a和b所在的两个集合
p[find(a)] = find(b)
d[find(a)] = distance
```
<!-- tabs:start -->
### **Python3**
@ -43,7 +104,34 @@
<!-- 这里可写当前语言的特殊实现逻辑 -->
```python
class Solution:
def largestArea(self, grid: List[str]) -> int:
m, n = len(grid), len(grid[0])
p = list(range(m * n + 1))
def find(x):
if p[x] != x:
p[x] = find(p[x])
return p[x]
for i in range(m):
for j in range(n):
if i == 0 or i == m - 1 or j == 0 or j == n - 1 or grid[i][j] == '0':
p[find(i * n + j)] = find(m * n)
else:
for x, y in [(-1, 0), (1, 0), (0, -1), (0, 1)]:
if grid[i + x][j + y] == '0' or grid[i][j] == grid[i + x][j + y]:
p[find(i * n + j)] = find((i + x) * n + j + y)
mp = collections.defaultdict(int)
res = 0
for i in range(m):
for j in range(n):
root = find(i * n + j)
if root != find(m * n):
mp[root] += 1
res = max(res, mp[root])
return res
```
### **Java**
@ -51,7 +139,50 @@
<!-- 这里可写当前语言的特殊实现逻辑 -->
```java
class Solution {
private int[] p;
private int[][] dirs = new int[][]{{0, -1}, {0, 1}, {1, 0}, {-1, 0}};
public int largestArea(String[] grid) {
int m = grid.length, n = grid[0].length();
p = new int[m * n + 1];
for (int i = 0; i < p.length; ++i) {
p[i] = i;
}
for (int i = 0; i < m; ++i) {
for (int j = 0; j < n; ++j) {
if (i == 0 || i == m - 1 || j == 0 || j == n - 1 || grid[i].charAt(j) == '0') {
p[find(i * n + j)] = find(m * n);
} else {
for (int[] e : dirs) {
if (grid[i + e[0]].charAt(j + e[1]) == '0' || grid[i].charAt(j) == grid[i + e[0]].charAt(j + e[1])) {
p[find(i * n + j)] = find((i + e[0]) * n + j + e[1]);
}
}
}
}
}
Map<Integer, Integer> mp = new HashMap<>();
int res = 0;
for (int i = 0; i < m; ++i) {
for (int j = 0; j < n; ++j) {
int root = find(i * n + j);
if (root != find(m * n)) {
mp.put(root, mp.getOrDefault(root, 0) + 1);
res = Math.max(res, mp.get(root));
}
}
}
return res;
}
private int find(int x) {
if (p[x] != x) {
p[x] = find(p[x]);
}
return p[x];
}
}
```
### **...**

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@ -0,0 +1,44 @@
class Solution {
private int[] p;
private int[][] dirs = new int[][]{{0, -1}, {0, 1}, {1, 0}, {-1, 0}};
public int largestArea(String[] grid) {
int m = grid.length, n = grid[0].length();
p = new int[m * n + 1];
for (int i = 0; i < p.length; ++i) {
p[i] = i;
}
for (int i = 0; i < m; ++i) {
for (int j = 0; j < n; ++j) {
if (i == 0 || i == m - 1 || j == 0 || j == n - 1 || grid[i].charAt(j) == '0') {
p[find(i * n + j)] = find(m * n);
} else {
for (int[] e : dirs) {
if (grid[i + e[0]].charAt(j + e[1]) == '0' || grid[i].charAt(j) == grid[i + e[0]].charAt(j + e[1])) {
p[find(i * n + j)] = find((i + e[0]) * n + j + e[1]);
}
}
}
}
}
Map<Integer, Integer> mp = new HashMap<>();
int res = 0;
for (int i = 0; i < m; ++i) {
for (int j = 0; j < n; ++j) {
int root = find(i * n + j);
if (root != find(m * n)) {
mp.put(root, mp.getOrDefault(root, 0) + 1);
res = Math.max(res, mp.get(root));
}
}
}
return res;
}
private int find(int x) {
if (p[x] != x) {
p[x] = find(p[x]);
}
return p[x];
}
}

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@ -0,0 +1,28 @@
class Solution:
def largestArea(self, grid: List[str]) -> int:
m, n = len(grid), len(grid[0])
p = list(range(m * n + 1))
def find(x):
if p[x] != x:
p[x] = find(p[x])
return p[x]
for i in range(m):
for j in range(n):
if i == 0 or i == m - 1 or j == 0 or j == n - 1 or grid[i][j] == '0':
p[find(i * n + j)] = find(m * n)
else:
for x, y in [(-1, 0), (1, 0), (0, -1), (0, 1)]:
if grid[i + x][j + y] == '0' or grid[i][j] == grid[i + x][j + y]:
p[find(i * n + j)] = find((i + x) * n + j + y)
mp = collections.defaultdict(int)
res = 0
for i in range(m):
for j in range(n):
root = find(i * n + j)
if root != find(m * n):
mp[root] += 1
res = max(res, mp[root])
return res