C++ 增广算法
我正在寻找一种算法来实现以下行为。如果当前元素和后续元素的总和小于或等于前一个元素,则总和将添加到新向量。以下是一些例子: 例1: 例2: 例3:C++ 增广算法,c++,algorithm,C++,Algorithm,我正在寻找一种算法来实现以下行为。如果当前元素和后续元素的总和小于或等于前一个元素,则总和将添加到新向量。以下是一些例子: 例1: 例2: 例3: 下面的代码可以工作,但在某些情况下,此代码可能会失败。我很确定一个月后我会忘记自己代码的细节。我想使用一个可靠的代码。std或boost中是否有标准算法可以实现我提到的功能 #include<vector> #include<iostream> void augmented_sort(const std::vector&l
下面的代码可以工作,但在某些情况下,此代码可能会失败。我很确定一个月后我会忘记自己代码的细节。我想使用一个可靠的代码。std或boost中是否有标准算法可以实现我提到的功能
#include<vector>
#include<iostream>
void augmented_sort(const std::vector<double>& invec, std::vector<double>& outvec)
{
if (invec.empty()) return;
outvec.push_back(invec[0]);
auto augment = [&invec](double& current, double previous, int& ai)
{
if (ai >= invec.size()) return false;
int start = ai;
current = invec[ai];
int ri = 1;
while(true)
{
current += invec[start+ri];
std::cout << "previous = " << previous << std::endl;
std::cout << "current = " << current << std::endl;
if (current <= previous)
{
++ri;
ai += 2;
std::cout << "ri = " << ri << std::endl;
std::cout << "ai = " << ai << std::endl;
if (start+ri >= invec.size())
return true;
}
else if (ai == start)
return false;
else
{
current -= invec[start+ri];
return true;
}
}
};
int ai = 1; // absolute index. start from second element.
double current;
double previous = invec[ai-1];
while (ai < invec.size())
{
bool success = augment(current, previous, ai);
if (success)
{
outvec.push_back(current);
previous = current;
}
else
{
outvec.push_back(invec[ai]);
previous = invec[ai];
ai += 1;
}
}
}
int main ()
{
//std::vector<double> invec = {17, 10, 6, 3, 2};
//std::vector<double> invec = {41, 15, 10, 5, 2};
std::vector<double> invec = {1, 1, 1, 1, 1};
std::vector<double> outvec;
augmented_sort(invec, outvec);
for (double d: outvec)
std::cout << "d = " << d << std::endl;
return 0;
}
#包括
#包括
无效增广_排序(常量std::vector和invec,std::vector和outvec)
{
if(invec.empty())返回;
输出向量推回(invec[0]);
自动增广=[&invec](双倍当前值、双倍先前值、整数和ai)
{
如果(ai>=invec.size())返回false;
int start=ai;
电流=invec[ai];
int ri=1;
while(true)
{
电流+=invec[start+ri];
我可能错了,但你的问题似乎太小了,没有标准的算法
然而,这里有一些简单得多的代码,它涉及在输入向量上循环一次,同时跟踪当前和,如果将当前元素添加到输出向量中,则只将当前元素添加到输出向量中,将导致和大于添加的最后一个元素:
void augmented_sort(const std::vector<double>& input, std::vector<double>& output)
{
if (input.empty())
return;
output.push_back(input[0]);
int sum = 0;
for (int i = 1; i < input.size(); i++)
{
if (sum + input[i] > output.back())
{
output.push_back(sum);
sum = 0;
}
sum += input[i];
}
if (input.size() > 1)
output.push_back(sum);
}
void增广排序(常量std::vector&input,std::vector&output)
{
if(input.empty())
返回;
输出。推回(输入[0]);
整数和=0;
对于(int i=1;ioutput.back())
{
输出。推回(总和);
总和=0;
}
总和+=输入[i];
}
if(input.size()>1)
输出。推回(总和);
}
如果您想让它按降序处理向量以外的任何东西(如前所述,需求似乎没有明确说明预期的行为),则需要进行一些更改。但可能会出现此代码失败的情况-单元测试在哪里?!:)@BartekBanachewicz我通过提供不同的输入向量来测试代码。
original vector: 1 | 1 | 1 | 1 | 1
new vector: 1 | 1 | 1 | 1 | 1
#include<vector>
#include<iostream>
void augmented_sort(const std::vector<double>& invec, std::vector<double>& outvec)
{
if (invec.empty()) return;
outvec.push_back(invec[0]);
auto augment = [&invec](double& current, double previous, int& ai)
{
if (ai >= invec.size()) return false;
int start = ai;
current = invec[ai];
int ri = 1;
while(true)
{
current += invec[start+ri];
std::cout << "previous = " << previous << std::endl;
std::cout << "current = " << current << std::endl;
if (current <= previous)
{
++ri;
ai += 2;
std::cout << "ri = " << ri << std::endl;
std::cout << "ai = " << ai << std::endl;
if (start+ri >= invec.size())
return true;
}
else if (ai == start)
return false;
else
{
current -= invec[start+ri];
return true;
}
}
};
int ai = 1; // absolute index. start from second element.
double current;
double previous = invec[ai-1];
while (ai < invec.size())
{
bool success = augment(current, previous, ai);
if (success)
{
outvec.push_back(current);
previous = current;
}
else
{
outvec.push_back(invec[ai]);
previous = invec[ai];
ai += 1;
}
}
}
int main ()
{
//std::vector<double> invec = {17, 10, 6, 3, 2};
//std::vector<double> invec = {41, 15, 10, 5, 2};
std::vector<double> invec = {1, 1, 1, 1, 1};
std::vector<double> outvec;
augmented_sort(invec, outvec);
for (double d: outvec)
std::cout << "d = " << d << std::endl;
return 0;
}
void augmented_sort(const std::vector<double>& input, std::vector<double>& output)
{
if (input.empty())
return;
output.push_back(input[0]);
int sum = 0;
for (int i = 1; i < input.size(); i++)
{
if (sum + input[i] > output.back())
{
output.push_back(sum);
sum = 0;
}
sum += input[i];
}
if (input.size() > 1)
output.push_back(sum);
}