From 497bb7cbf358a4db63dcd32650513ae7e949bedd Mon Sep 17 00:00:00 2001 From: hui <760261797@qq.com> Date: Tue, 29 Oct 2024 16:40:27 +0800 Subject: [PATCH 1/3] =?UTF-8?q?=E4=BF=AE=E6=AD=A3=E7=AC=94=E8=AF=AF?= =?UTF-8?q?=EF=BC=8C=E6=95=B0=E7=BB=84=E4=B8=8E=E5=9B=BE=E7=89=87=E4=B8=8D?= =?UTF-8?q?=E4=B8=80=E8=87=B4?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0376.摆动序列.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/problems/0376.摆动序列.md b/problems/0376.摆动序列.md index 9e6714ce..88b59ffc 100644 --- a/problems/0376.摆动序列.md +++ b/problems/0376.摆动序列.md @@ -72,7 +72,7 @@ #### 情况一：上下坡中有平坡 -例如 [1,2,2,2,1]这样的数组，如图： +例如 [1,2,2,2,2,1]这样的数组，如图： ![](https://code-thinking-1253855093.file.myqcloud.com/pics/20230106170449.png) From 03f60b691f17e97d50707b0fc3af2f48fb2063c5 Mon Sep 17 00:00:00 2001 From: markwang Date: Fri, 1 Nov 2024 14:15:14 +0800 Subject: [PATCH 2/3] =?UTF-8?q?992.=E6=8C=89=E5=A5=87=E5=81=B6=E6=8E=92?= =?UTF-8?q?=E5=BA=8F=E6=95=B0=E7=BB=84II=E6=9B=B4=E6=96=B0=E9=A2=98?= =?UTF-8?q?=E7=9B=AE=E6=8F=8F=E8=BF=B0=EF=BC=8C=E5=A2=9E=E5=8A=A0Go?= =?UTF-8?q?=E6=96=B9=E6=B3=95=E4=BA=8C=E5=92=8C=E6=96=B9=E6=B3=95=E4=B8=89?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0922.按奇偶排序数组II.md | 77 +++++++++++++++++------- 1 file changed, 54 insertions(+), 23 deletions(-) diff --git a/problems/0922.按奇偶排序数组II.md b/problems/0922.按奇偶排序数组II.md index 1ac6800c..28680dbf 100644 --- a/problems/0922.按奇偶排序数组II.md +++ b/problems/0922.按奇偶排序数组II.md @@ -11,9 +11,9 @@ [力扣题目链接](https://leetcode.cn/problems/sort-array-by-parity-ii/) -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。 +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。 -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。 +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。 你可以返回任何满足上述条件的数组作为答案。 @@ -35,17 +35,17 @@ ```CPP class Solution { public: - vector sortArrayByParityII(vector& A) { - vector even(A.size() / 2); // 初始化就确定数组大小，节省开销 - vector odd(A.size() / 2); - vector result(A.size()); + vector sortArrayByParityII(vector& nums) { + vector even(nums.size() / 2); // 初始化就确定数组大小，节省开销 + vector odd(nums.size() / 2); + vector result(nums.size()); int evenIndex = 0; int oddIndex = 0; int resultIndex = 0; - // 把A数组放进偶数数组，和奇数数组 - for (int i = 0; i < A.size(); i++) { - if (A[i] % 2 == 0) even[evenIndex++] = A[i]; - else odd[oddIndex++] = A[i]; + // 把nums数组放进偶数数组，和奇数数组 + for (int i = 0; i < nums.size(); i++) { + if (nums[i] % 2 == 0) even[evenIndex++] = nums[i]; + else odd[oddIndex++] = nums[i]; } // 把偶数数组，奇数数组分别放进result数组中 for (int i = 0; i < evenIndex; i++) { @@ -62,22 +62,22 @@ public: ### 方法二 -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： +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： ```CPP class Solution { public: - vector sortArrayByParityII(vector& A) { - vector result(A.size()); + vector sortArrayByParityII(vector& nums) { + vector result(nums.size()); int evenIndex = 0; // 偶数下标 int oddIndex = 1; // 奇数下标 - for (int i = 0; i < A.size(); i++) { - if (A[i] % 2 == 0) { - result[evenIndex] = A[i]; + for (int i = 0; i < nums.size(); i++) { + if (nums[i] % 2 == 0) { + result[evenIndex] = nums[i]; evenIndex += 2; } else { - result[oddIndex] = A[i]; + result[oddIndex] = nums[i]; oddIndex += 2; } } @@ -96,15 +96,15 @@ public: ```CPP class Solution { public: - vector sortArrayByParityII(vector& A) { + vector sortArrayByParityII(vector& nums) { int oddIndex = 1; - for (int i = 0; i < A.size(); i += 2) { - if (A[i] % 2 == 1) { // 在偶数位遇到了奇数 - while(A[oddIndex] % 2 != 0) oddIndex += 2; // 在奇数位找一个偶数 - swap(A[i], A[oddIndex]); // 替换 + for (int i = 0; i < nums.size(); i += 2) { + if (nums[i] % 2 == 1) { // 在偶数位遇到了奇数 + while(nums[oddIndex] % 2 != 0) oddIndex += 2; // 在奇数位找一个偶数 + swap(nums[i], nums[oddIndex]); // 替换 } } - return A; + return nums; } }; ``` @@ -253,6 +253,37 @@ func sortArrayByParityII(nums []int) []int { } return result; } + +// 方法二 +func sortArrayByParityII(nums []int) []int { + result := make([]int, len(nums)) + evenIndex := 0 // 偶数下标 + oddIndex := 1 // 奇数下标 + for _, v := range nums { + if v % 2 == 0 { + result[evenIndex] = v + evenIndex += 2 + } else { + result[oddIndex] = v + oddIndex += 2 + } + } + return result +} + +// 方法三 +func sortArrayByParityII(nums []int) []int { + oddIndex := 1 + for i := 0; i < len(nums); i += 2 { + if nums[i] % 2 == 1 { // 在偶数位遇到了奇数 + for nums[oddIndex] % 2 != 0 { + oddIndex += 2 // 在奇数位找一个偶数 + } + nums[i], nums[oddIndex] = nums[oddIndex], nums[i] + } + } + return nums +} ``` ### JavaScript From 4a9cfb56048e10e688745605289cbe76de84a0bf Mon Sep 17 00:00:00 2001 From: Tony Date: Fri, 6 Dec 2024 17:43:53 +0800 Subject: [PATCH 3/3] =?UTF-8?q?=E7=8E=B0=E6=9C=89=E8=A7=A3=E6=B3=95python?= =?UTF-8?q?=E8=B6=85=E6=97=B6=EF=BC=8C=E9=80=9A=E8=BF=87=E5=87=8F=E5=B0=91?= =?UTF-8?q?=E9=80=92=E5=BD=92=E6=AC=A1=E6=95=B0=E4=BC=98=E5=8C=96?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0037.解数独.md | 80 +++++++++++++++++++++++--------------- 1 file changed, 48 insertions(+), 32 deletions(-) diff --git a/problems/0037.解数独.md b/problems/0037.解数独.md index 6a9f69bd..5f3f881c 100644 --- a/problems/0037.解数独.md +++ b/problems/0037.解数独.md @@ -366,40 +366,56 @@ class Solution: """ Do not return anything, modify board in-place instead. """ - self.backtracking(board) + row_used = [set() for _ in range(9)] + col_used = [set() for _ in range(9)] + box_used = [set() for _ in range(9)] + for row in range(9): + for col in range(9): + num = board[row][col] + if num == ".": + continue + row_used[row].add(num) + col_used[col].add(num) + box_used[(row // 3) * 3 + col // 3].add(num) + self.backtracking(0, 0, board, row_used, col_used, box_used) - def backtracking(self, board: List[List[str]]) -> bool: - # 若有解，返回True；若无解，返回False - for i in range(len(board)): # 遍历行 - for j in range(len(board[0])): # 遍历列 - # 若空格内已有数字，跳过 - if board[i][j] != '.': continue - for k in range(1, 10): - if self.is_valid(i, j, k, board): - board[i][j] = str(k) - if self.backtracking(board): return True - board[i][j] = '.' - # 若数字1-9都不能成功填入空格，返回False无解 - return False - return True # 有解 + def backtracking( + self, + row: int, + col: int, + board: List[List[str]], + row_used: List[List[int]], + col_used: List[List[int]], + box_used: List[List[int]], + ) -> bool: + if row == 9: + return True - def is_valid(self, row: int, col: int, val: int, board: List[List[str]]) -> bool: - # 判断同一行是否冲突 - for i in range(9): - if board[row][i] == str(val): - return False - # 判断同一列是否冲突 - for j in range(9): - if board[j][col] == str(val): - return False - # 判断同一九宫格是否有冲突 - start_row = (row // 3) * 3 - start_col = (col // 3) * 3 - for i in range(start_row, start_row + 3): - for j in range(start_col, start_col + 3): - if board[i][j] == str(val): - return False - return True + next_row, next_col = (row, col + 1) if col < 8 else (row + 1, 0) + if board[row][col] != ".": + return self.backtracking( + next_row, next_col, board, row_used, col_used, box_used + ) + + for num in map(str, range(1, 10)): + if ( + num not in row_used[row] + and num not in col_used[col] + and num not in box_used[(row // 3) * 3 + col // 3] + ): + board[row][col] = num + row_used[row].add(num) + col_used[col].add(num) + box_used[(row // 3) * 3 + col // 3].add(num) + if self.backtracking( + next_row, next_col, board, row_used, col_used, box_used + ): + return True + board[row][col] = "." + row_used[row].remove(num) + col_used[col].remove(num) + box_used[(row // 3) * 3 + col // 3].remove(num) + return False ``` ### Go