algorithm-dp

algorithm-dp

problem

1. “花店橱窗布置问题”试题
LITTLE SHOP OF FLOWERS

PROBLEM
You want to arrange the window of your flower shop in a most pleasant way. You have F bunches of flowers, each being of a different kind, and at least as many vases ordered in a row. The vases are glued onto the shelf and are numbered consecutively 1```` through V, where V is the number of vases, from left to right so that the vase 1 is the leftmost, and the vase V is the rightmost vase. The bunches are moveable and are uniquely identified by integers between 1 and F. These id-numbers have a significance: They determine the required order of appearance of the flower bunches in the row of vases so that the bunch i must be in a vase to the left of the vase containing bunch j whenever i < j. Suppose, for example, you have bunch of azaleas (id-number=1), a bunch of begonias (id-number=2) and a bunch of carnations (id-number=3). Now, all the bunches must be put into the vases keeping their id-numbers in order. The bunch of azaleas must be in a vase to the left of begonias, and the bunch of begonias must be in a vase to the left of carnations. If there are more vases than bunches of flowers then the excess will be left empty. A vase can hold only one bunch of flowers.

Each vase has a distinct characteristic (just like flowers do). Hence, putting a bunch of flowers in a vase results in a certain aesthetic value, expressed by an integer. The aesthetic values are presented in a table as shown below. Leaving a vase empty has an aesthetic value of 0.


VASES

1
2
3
4
5
Bunches
1 (azaleas)
7
23
-5
-24
16
2 (begonias)
5
21
-4
10
23
3 (carnations)
-21
5
-4
-20
20
According to the table, azaleas, for example, would look great in vase 2, but they would look awful in vase 4.

To achieve the most pleasant effect you have to maximize the sum of aesthetic values for the arrangement while keeping the required ordering of the flowers. If more than one arrangement has the maximal sum value, any one of them will be acceptable. You have to produce exactly one arrangement.

ASSUMPTIONS
1 <= F <= 100 where F is the number of the bunches of flowers. The bunches are numbered 1 through F.
F <= V <= 100 where V is the number of vases.
-50 <= Aij <= 50 where Aij is the aesthetic value obtained by putting the flower bunch i into the vase j.

INPUT
The input is a text file named flower.inp.
The first line contains two numbers: F, V.
The following F lines: Each of these lines contains V integers, so that Aij is given as the jth number on the (i+1)st line of the input file.

OUTPUT
The output must be a text file named flower.out consisting of two lines:
The first line will contain the sum of aesthetic values for your arrangement.
The second line must present the arrangement as a list of F numbers, so that the k’th number on this line identifies the vase in which the bunch k is put.

EXAMPLE
flower.inp:
3 5
7 23 -5 -24 16
5 21 -4 10 23
-21 5 -4 -20 20

flower.out:
53
2 4 5

EVALUATION
Your program will be allowed to run 2 seconds.
No partial credit can be obtained for a test case.

solution

n维坐标方式,每一束花代表一维坐标
叠加方式构建表,迭代方式计算最优值

1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,9): error : ‘void CANopenClient::cleanupTimeoutRequests()’ is private within this context 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,9): error : 437 | cleanupTimeoutRequests(); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,9): error : | ^~~~~~~~~~~~~~~~~~~~~~ 1>C:\shui\web1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,9): error : ‘void CANopenClient::cleanupTimeoutRequests()’ is private within this context 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,9): error : 437 | cleanupTimeoutRequests(); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,9): error : | ^~~~~~~~~~~~~~~~~~~~~~ 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : declared private here 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : 112 | void cleanupTimeoutRequests(); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : | ^~~~~~~~~~~~~~~~~~~~~~ 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,31): error : ‘void CANopenClient::cleanupTimeoutRequests()’ is private within this context 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,31): error : 437 | cleanupTimeoutRequests(); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,31): error : | ~~~~~~~~~~~~~~~~~~~~~~^~ 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : declared private here 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : 112 | void cleanupTimeoutRequests(); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : | ^~~~~~~~~~~~~~~~~~~~~~ 1>canopen_parser.cpp 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(22,13): error : ‘memset’ was not declared in this scope 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(22,13): error : 22 | memset(data, 0, sizeof(data)); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(22,13): error : | ^~~~~~ 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(10,1): message : ‘memset’ is defined in header ‘<cstring>’; did you forget to ‘#include <cstring>’? 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(10,1): message : 9 | #include <functional> 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(10,1): message : +++ |+#include <cstring> 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(10,1): message : 10 | 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(29,13): error : ‘memset’ was not declared in this scope 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(29,13): error : 29 | memset(data, 0, sizeof(data)); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(29,13): error : | ^~~~~~ 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(29,13): message : ‘memset’ is defined in header ‘<cstring>’; did you forget to ‘#include <cstring>’? 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(31,17): error : ‘memcpy’ was not declared in this scope 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(31,17): error : 31 | memcpy(data, canData, length); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(31,17): error : | \comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : declared private here 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : 112 | void cleanupTimeoutRequests(); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : | ^~~~~~~~~~~~~~~~~~~~~~ 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,31): error : ‘void CANopenClient::cleanupTimeoutRequests()’ is private within this context 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,31): error : 437 | cleanupTimeoutRequests(); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_master.cpp(437,31): error : | ~~~~~~~~~~~~~~~~~~~~~~^~ 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : declared private here 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : 112 | void cleanupTimeoutRequests(); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_client.h(112,10): message : | ^~~~~~~~~~~~~~~~~~~~~~ 1>canopen_parser.cpp 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(22,13): error : ‘memset’ was not declared in this scope 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(22,13): error : 22 | memset(data, 0, sizeof(data)); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(22,13): error : | ^~~~~~ 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(10,1): message : ‘memset’ is defined in header ‘<cstring>’; did you forget to ‘#include <cstring>’? 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(10,1): message : 9 | #include <functional> 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(10,1): message : +++ |+#include <cstring> 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(10,1): message : 10 | 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(29,13): error : ‘memset’ was not declared in this scope 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(29,13): error : 29 | memset(data, 0, sizeof(data)); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(29,13): error : | ^~~~~~ 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(29,13): message : ‘memset’ is defined in header ‘<cstring>’; did you forget to ‘#include <cstring>’? 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(31,17): error : ‘memcpy’ was not declared in this scope 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(31,17): error : 31 | memcpy(data, canData, length); 1>C:\shui\web\comm\x86\bb\aaa-demo\93-dp\11-dp\11-dp\..\..\canopen_parser.h(31,17): error : |
最新发布
11-16
<think> 首先,用户的问题是关于编译错误的: 1. "'void CANopenClient::cleanupTimeoutRequests()' 是私有成员无法访问" 2. "'memset' 和 'memcpy' 未声明的编译错误" 我需要基于提供的引用内容来回答。引用包括: - 引用[1]:关于z_tls_copy函数使用memcpy和memset。 - 引用[2]:关于memcpy、strcpy、sprintf的区别。 - 引用[3]:关于malloc/free vs new/delete,以及内存分配原理。 - 引用[4]:关于动态对象分配的接口rt_object_allocate。 用户的问题集中在两个错误: 1. **私有成员访问错误**:用户试图访问一个私有函数 `CANopenClient::cleanupTimeoutRequests()`。 2. **函数未声明错误**:`memset` 和 `memcpy` 未声明,可能缺少头文件。 从引用中提取相关信息: - 对于 `memcpy` 和 `memset`,引用[1]展示了它们的使用,引用[2]讨论了它们的功能。这表明这些函数需要包含适当的头文件。 - 在C/C++中,`memcpy` 和 `memset` 需要包含 `<cstring>` 或 `<string.h>`。 - 对于私有成员访问错误,引用中没有直接相关的内容。但引用[4]提到了RT-Thread的对象分配接口,暗示这可能是在嵌入式或RTOS环境中(如RT-Thread)。用户提到的 `CANopenClient` 类可能来自CANopen协议栈。 用户的问题:"void CANopenClient::cleanupTimeoutRequests()’是私有成员无法访问" 意味着用户可能在一个不允许访问 `cleanupTimeoutRequests()` 的地方调用了它,因为这个函数是 `CANopenClient` 类的私有成员。 解决步骤: 1. **私有成员访问错误**: - 检查 `cleanupTimeoutRequests()` 是否应该被外部访问。如果是,需要将其声明为 `public`。 - 如果它是私有的,可能是内部使用,用户不应该直接调用它。用户应该检查代码逻辑,确保只在类内部调用它。 - 在RT-Thread或类似框架中,类设计可能有特定约定。 2. **memcpy 和 memset 未声明**: - 添加头文件 `#include <cstring>` 或 `#include <string.h>`。 - 引用[1]中有使用示例,说明这些函数需要包含头文件。 现在,构建回答: - 回答必须用中文。 - 结构清晰,逐步解决问题。 - 确保真实可靠:基于C++和嵌入式开发常识。 - 添加引用标识:在引用相关段落时添加 [^1], [^2], [^3], [^4]。 回答结构: 1. **解释错误原因**: - 私有成员错误:函数被声明为私有,外部无法访问。 - 未声明函数:缺少头文件包含。 2. **提供解决方案**: - 对于私有成员错误: - 如果应该公开,修改类定义,将函数移到 `public` 部分。 - 如果不应直接调用,检查代码逻辑,使用公共接口。 - 对于 `memcpy` 和 `memset` 错误: - 包含头文件 `<cstring>` 或 `<string.h>`。 - 引用[1]展示了这些函数的使用。 3. **生成相关问题**:在末尾添加相关问题。 4. **引用添加**:在回答中自然地添加引用标识。 最终回答: - 先解决私有成员错误。 - 然后解决函数未声明错误。 - 添加相关问题。 </think> ### 解决编译错误的方法 您的编译错误涉及两个问题:1. 私有成员函数访问错误;2. `memset` 和 `memcpy` 函数未声明。我将逐步解释原因并提供解决方案。这些问题与C++类设计和内存操作函数的使用相关。以下是详细说明: #### 1. **解决 `void CANopenClient::cleanupTimeoutRequests()’是私有成员无法访问` 错误** **错误原因**: `cleanupTimeoutRequests()` 是 `CANopenClient` 类的私有成员函数(声明在类的 `private:` 部分)。这表示它只能在类内部(如其他成员函数中)调用,不能在类外部(如全局函数或其他类的函数)直接访问。尝试在外部调用它会导致编译错误。 **解决方案**: - **方案A:修改类定义(如果函数需要公开)** 如果 `cleanupTimeoutRequests()` 是公共接口的一部分(例如,需要被其他模块调用),将其移动到 `public:` 部分。修改类头文件(如 `CANopenClient.h`): ```cpp class CANopenClient { public: // 将函数移到 public 区域 void cleanupTimeoutRequests(); // 确保函数声明为 public // ... 其他成员函数 ... private: // ... 私有成员 ... }; ``` 然后,在调用处(如另一个文件)直接使用 `object.cleanupTimeoutRequests()`。 - **方案B:通过公共接口间接调用(如果函数应保持私有)** 如果 `cleanupTimeoutRequests()` 是内部实现细节(如定时器回调),不应直接暴露: - 添加一个公共函数(如 `public: void checkRequests()`),在内部调用 `cleanupTimeoutRequests()`。 - 示例代码: ```cpp class CANopenClient { public: void checkRequests() { cleanupTimeoutRequests(); // 在类内部调用私有函数 } private: void cleanupTimeoutRequests(); // 保持私有 }; ``` 外部代码调用 `object.checkRequests()` 即可。 - **方案C:检查框架设计(如RT-Thread)** 在嵌入式系统(如RT-Thread)中,类可能遵循特定设计模式。确保调用点位于类内部(如事件处理函数中)。引用[4]提到对象初始化和动态分配接口类似,请确认 `cleanupTimeoutRequests()` 是否应在对象生命周期方法中使用[^4]。 **注意事项**: 如果 `CANopenClient` 是第三方库的一部分,查阅其文档,确认该函数是否为公开API。避免修改库代码,优先使用方案B。 #### 2. **解决 `memset` 和 `memcpy` 未声明的编译错误** **错误原因**: `memset` 和 `memcpy` 是C标准库函数,用于内存块操作: - `memcpy(dest, src, size)`:复制内存块(如引用[2]所述,操作任意内存地址)。 - `memset(dest, value, size)`:设置内存块为特定值(如清零)。 在C++中,这些函数需要包含头文件 `<cstring>` 或 `<string.h>`。未包含头文件会导致编译器无法识别函数声明。 **解决方案**: - **添加头文件包含** 在调用 `memset` 或 `memcpy` 的源文件顶部添加: ```cpp #include <cstring> // 推荐C++风格,或使用 #include <string.h> ``` 引用[1]中的 `z_tls_copy` 函数就使用了 `memcpy` 和 `memset`,正确包含头文件后即可编译[^1]。 - **检查函数使用场景** - 如果用于初始化对象(如清零结构体),确保目标内存是合法分配: ```cpp struct MyStruct data; memset(&data, 0, sizeof(data)); // 正确示例:清零结构体 ``` - 避免在非POD(Plain Old Data)类型(如带虚函数的类)上使用,可能破坏内部状态。引用[3]强调,`malloc/free` 不适用于动态对象构造函数/析构函数,类似地,`memset/memcpy` 可能绕过类语义[^3]。 - **替代方案(如C++特性)** 如果安全性和可读性优先,使用C++替代: - 用 `std::copy` 或 `std::fill`(需 `<algorithm>` 头文件): ```cpp #include <algorithm> std::copy(src, src + size, dest); // 替代 memcpy std::fill(dest, dest + size, 0); // 替代 memset(0) ``` - 用构造函数初始化对象,避免手动内存操作。 **完整示例(结合两个问题)**: 假设在 `CANopenClient` 类的实现中: ```cpp #include <cstring> // 解决 memset/memcpy 未声明错误 class CANopenClient { public: void checkRequests() { // 公共接口 cleanupTimeoutRequests(); // 内部调用私有函数 } private: void cleanupTimeoutRequests() { // 私有函数 char buffer[128]; memset(buffer, 0, sizeof(buffer)); // 正确使用 memset // ... 其他逻辑 ... } }; ``` #### 总结步骤 1. **检查类定义**:确认 `cleanupTimeoutRequests()` 的访问权限,调整或添加公共包装器。 2. **添加头文件**:在源文件中包含 `<cstring>`。 3. **编译验证**:重新编译,确保错误消失。 如果问题在RT-Thread等嵌入式环境中,请参考框架文档确认内存操作函数的使用约定(引用[1]和引用[4]涉及内存初始化和对象分配)[^1][^4]。
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