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Commit c865c46

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Merge branch 'youngyangyang04:master' into master
2 parents fb9186f + 4d36947 commit c865c46

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3 files changed

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-58
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3 files changed

+105
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‎problems/0037.解数独.md

Lines changed: 50 additions & 34 deletions
Original file line numberDiff line numberDiff line change
@@ -366,40 +366,56 @@ class Solution:
366366
"""
367367
Do not return anything, modify board in-place instead.
368368
"""
369-
self.backtracking(board)
370-
371-
def backtracking(self, board: List[List[str]]) -> bool:
372-
# 若有解,返回True;若无解,返回False
373-
for i in range(len(board)): # 遍历行
374-
for j in range(len(board[0])): # 遍历列
375-
# 若空格内已有数字,跳过
376-
if board[i][j] != '.': continue
377-
for k in range(1, 10):
378-
if self.is_valid(i, j, k, board):
379-
board[i][j] = str(k)
380-
if self.backtracking(board): return True
381-
board[i][j] = '.'
382-
# 若数字1-9都不能成功填入空格,返回False无解
383-
return False
384-
return True # 有解
385-
386-
def is_valid(self, row: int, col: int, val: int, board: List[List[str]]) -> bool:
387-
# 判断同一行是否冲突
388-
for i in range(9):
389-
if board[row][i] == str(val):
390-
return False
391-
# 判断同一列是否冲突
392-
for j in range(9):
393-
if board[j][col] == str(val):
394-
return False
395-
# 判断同一九宫格是否有冲突
396-
start_row = (row // 3) * 3
397-
start_col = (col // 3) * 3
398-
for i in range(start_row, start_row + 3):
399-
for j in range(start_col, start_col + 3):
400-
if board[i][j] == str(val):
401-
return False
402-
return True
369+
row_used = [set() for _ in range(9)]
370+
col_used = [set() for _ in range(9)]
371+
box_used = [set() for _ in range(9)]
372+
for row in range(9):
373+
for col in range(9):
374+
num = board[row][col]
375+
if num == ".":
376+
continue
377+
row_used[row].add(num)
378+
col_used[col].add(num)
379+
box_used[(row // 3) * 3 + col // 3].add(num)
380+
self.backtracking(0, 0, board, row_used, col_used, box_used)
381+
382+
def backtracking(
383+
self,
384+
row: int,
385+
col: int,
386+
board: List[List[str]],
387+
row_used: List[List[int]],
388+
col_used: List[List[int]],
389+
box_used: List[List[int]],
390+
) -> bool:
391+
if row == 9:
392+
return True
393+
394+
next_row, next_col = (row, col + 1) if col < 8 else (row + 1, 0)
395+
if board[row][col] != ".":
396+
return self.backtracking(
397+
next_row, next_col, board, row_used, col_used, box_used
398+
)
399+
400+
for num in map(str, range(1, 10)):
401+
if (
402+
num not in row_used[row]
403+
and num not in col_used[col]
404+
and num not in box_used[(row // 3) * 3 + col // 3]
405+
):
406+
board[row][col] = num
407+
row_used[row].add(num)
408+
col_used[col].add(num)
409+
box_used[(row // 3) * 3 + col // 3].add(num)
410+
if self.backtracking(
411+
next_row, next_col, board, row_used, col_used, box_used
412+
):
413+
return True
414+
board[row][col] = "."
415+
row_used[row].remove(num)
416+
col_used[col].remove(num)
417+
box_used[(row // 3) * 3 + col // 3].remove(num)
418+
return False
403419
```
404420

405421
### Go

‎problems/0376.摆动序列.md

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -72,7 +72,7 @@
7272

7373
#### 情况一:上下坡中有平坡
7474

75-
例如 [1,2,2,2,1]这样的数组,如图:
75+
例如 [1,2,2,2,2,1]这样的数组,如图:
7676

7777
![](https://code-thinking-1253855093.file.myqcloud.com/pics/20230106170449.png)
7878

‎problems/0922.按奇偶排序数组II.md

Lines changed: 54 additions & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -11,9 +11,9 @@
1111

1212
[力扣题目链接](https://leetcode.cn/problems/sort-array-by-parity-ii/)
1313

14-
给定一个非负整数数组 A, A 中一半整数是奇数,一半整数是偶数。
14+
给定一个非负整数数组 nums, nums 中一半整数是奇数,一半整数是偶数。
1515

16-
对数组进行排序,以便当 A[i] 为奇数时,i 也是奇数;当 A[i] 为偶数时, i 也是偶数。
16+
对数组进行排序,以便当 nums[i] 为奇数时,i 也是奇数;当 nums[i] 为偶数时, i 也是偶数。
1717

1818
你可以返回任何满足上述条件的数组作为答案。
1919

@@ -35,17 +35,17 @@
3535
```CPP
3636
class Solution {
3737
public:
38-
vector<int> sortArrayByParityII(vector<int>& A) {
39-
vector<int> even(A.size() / 2); // 初始化就确定数组大小,节省开销
40-
vector<int> odd(A.size() / 2);
41-
vector<int> result(A.size());
38+
vector<int> sortArrayByParityII(vector<int>& nums) {
39+
vector<int> even(nums.size() / 2); // 初始化就确定数组大小,节省开销
40+
vector<int> odd(nums.size() / 2);
41+
vector<int> result(nums.size());
4242
int evenIndex = 0;
4343
int oddIndex = 0;
4444
int resultIndex = 0;
45-
// 把A数组放进偶数数组,和奇数数组
46-
for (int i = 0; i < A.size(); i++) {
47-
if (A[i] % 2 == 0) even[evenIndex++] = A[i];
48-
else odd[oddIndex++] = A[i];
45+
// 把nums数组放进偶数数组,和奇数数组
46+
for (int i = 0; i < nums.size(); i++) {
47+
if (nums[i] % 2 == 0) even[evenIndex++] = nums[i];
48+
else odd[oddIndex++] = nums[i];
4949
}
5050
// 把偶数数组,奇数数组分别放进result数组中
5151
for (int i = 0; i < evenIndex; i++) {
@@ -62,22 +62,22 @@ public:
6262
6363
### 方法二
6464
65-
以上代码我是建了两个辅助数组,而且A数组还相当于遍历了两次,用辅助数组的好处就是思路清晰,优化一下就是不用这两个辅助树,代码如下:
65+
以上代码我是建了两个辅助数组,而且nums数组还相当于遍历了两次,用辅助数组的好处就是思路清晰,优化一下就是不用这两个辅助数组,代码如下:
6666
6767
```CPP
6868
class Solution {
6969
public:
70-
vector<int> sortArrayByParityII(vector<int>& A) {
71-
vector<int> result(A.size());
70+
vector<int> sortArrayByParityII(vector<int>& nums) {
71+
vector<int> result(nums.size());
7272
int evenIndex = 0; // 偶数下标
7373
int oddIndex = 1; // 奇数下标
74-
for (int i = 0; i < A.size(); i++) {
75-
if (A[i] % 2 == 0) {
76-
result[evenIndex] = A[i];
74+
for (int i = 0; i < nums.size(); i++) {
75+
if (nums[i] % 2 == 0) {
76+
result[evenIndex] = nums[i];
7777
evenIndex += 2;
7878
}
7979
else {
80-
result[oddIndex] = A[i];
80+
result[oddIndex] = nums[i];
8181
oddIndex += 2;
8282
}
8383
}
@@ -96,15 +96,15 @@ public:
9696
```CPP
9797
class Solution {
9898
public:
99-
vector<int> sortArrayByParityII(vector<int>& A) {
99+
vector<int> sortArrayByParityII(vector<int>& nums) {
100100
int oddIndex = 1;
101-
for (int i = 0; i < A.size(); i += 2) {
102-
if (A[i] % 2 == 1) { // 在偶数位遇到了奇数
103-
while(A[oddIndex] % 2 != 0) oddIndex += 2; // 在奇数位找一个偶数
104-
swap(A[i], A[oddIndex]); // 替换
101+
for (int i = 0; i < nums.size(); i += 2) {
102+
if (nums[i] % 2 == 1) { // 在偶数位遇到了奇数
103+
while(nums[oddIndex] % 2 != 0) oddIndex += 2; // 在奇数位找一个偶数
104+
swap(nums[i], nums[oddIndex]); // 替换
105105
}
106106
}
107-
return A;
107+
return nums;
108108
}
109109
};
110110
```
@@ -253,6 +253,37 @@ func sortArrayByParityII(nums []int) []int {
253253
}
254254
return result;
255255
}
256+
257+
// 方法二
258+
func sortArrayByParityII(nums []int) []int {
259+
result := make([]int, len(nums))
260+
evenIndex := 0 // 偶数下标
261+
oddIndex := 1 // 奇数下标
262+
for _, v := range nums {
263+
if v % 2 == 0 {
264+
result[evenIndex] = v
265+
evenIndex += 2
266+
} else {
267+
result[oddIndex] = v
268+
oddIndex += 2
269+
}
270+
}
271+
return result
272+
}
273+
274+
// 方法三
275+
func sortArrayByParityII(nums []int) []int {
276+
oddIndex := 1
277+
for i := 0; i < len(nums); i += 2 {
278+
if nums[i] % 2 == 1 { // 在偶数位遇到了奇数
279+
for nums[oddIndex] % 2 != 0 {
280+
oddIndex += 2 // 在奇数位找一个偶数
281+
}
282+
nums[i], nums[oddIndex] = nums[oddIndex], nums[i]
283+
}
284+
}
285+
return nums
286+
}
256287
```
257288

258289
### JavaScript

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