Question

我似乎无法弄清楚为什么我在下面的突出显示行的编译时收到错误消息。错误消息是＆＃34; ValueError：需要2个以上的值才能解压＆＃34; ...提前感谢您的帮助

#include <iostream>
using namespace std;

class ManagedArray
{
    private:
        int numberOfElements;
        float *elements;


    public:


        ManagedArray(): numberOfElements(0), elements(NULL){}
        int size();
        float get(int index);
        void add(float value);
        ManagedArray(ManagedArray & ma);
        ~ManagedArray() {delete [] elements;}




};


ManagedArray::ManagedArray(ManagedArray & ma):numberOfElements(ma.numberOfElements) 
{
    elements = ma.elements;
}

int ManagedArray::size()
{
    return numberOfElements;
}

float ManagedArray::get(int index)
{
    return elements[index];
}

void ManagedArray::add(float value)
{
    float * BiggerArray = new float[numberOfElements+1];
    if(elements != NULL)
    {
        // copy the old elements into the biggerArray
        for(int i = 0; i < numberOfElements; i++)
        {
            BiggerArray[i] = elements[i];
        }
        // the old array is not needed anymore, we have a better copy
        this->~ManagedArray();
    }
    elements = BiggerArray;
    numberOfElements = numberOfElements+1;
    // put the new number into the last element of the array
    elements[numberOfElements-1] = value;
}

void print(ManagedArray ma)
{
    // print the stored numbers
    cout << "Entered numbers: " << endl;
    cout << "{";
    for(int i = 0; i < ma.size(); ++i)
    {
        if(i > 0)
        {
            cout << ", ";
        }
        cout << ma.get(i);
    }
    cout << "}" << endl;

    float sum = 0;
    for(int i = 0; i < ma.size(); ++i)
    {
        sum += ma.get(i);
    }
    cout << "total: " << sum << endl;
    cout << "average: " << (sum / ma.size()) << endl;
}

int main()
{
    float userInput;
    ManagedArray elementArray;
    bool addingNumbersToTheList;
    cout << "Keep entering numbers. Enter a non-number to stop." << endl;
    do
    {
        cin >> userInput;
        addingNumbersToTheList = !std::cin.fail();
        if(addingNumbersToTheList) {
            elementArray.add(userInput);

        }
    }
    while(addingNumbersToTheList);

    // fix cin after intentionally breaking it above.
    if(std::cin.fail())
    {
        std::cin.clear();
        while(std::cin.get() != '\n');
    }
    bool hasNumbers = elementArray.size() > 0;
    if(hasNumbers) {
        ManagedArray copyArray(elementArray);
        cout << "printing elementArray:\n";
        print(elementArray);
        cout << "\nprinting copyArray:\n";
        print(copyArray);



    }
    else
    {
        cout << "no numbers entered." << endl;
    }
    cin.get();
    cin.get();
    return 0;
}

这是我的主要代码

def divConHelper(array, first, center, last):
    sumRight = float('-inf') #assign impossibly low number
    sumLeft = float('-inf') #assign impossibly low number
    leftIndexMax = 0
    rightIndexMax = 0 

    # Determine crossover max toward left
    currentLTotal = 0
    for i in range(first, center): 
    #Incrementally add values to sum
      currentLTotal += sum(array[i:center-1])
    #if the total is greater than the sumLeft, replace
      if currentLTotal > sumLeft:
        sumLeft = currentLTotal   
        leftIndexMax = i 

  # Determine crossover max toward right
    currentRTotal=0
    for i in range(center+1, last):
    #Incrementally add values to sum
      currentRTotal += sum(array[center:i+1])
    #if the rightTotal is greater than the sumRight, replace
      if currentRTotal > sumRight:
        sumRight = currentRTotal
        rightIndexMax = i+1 

    bothTotal = sumRight + sumLeft

    return(leftIndexMax, rightIndexMax, bothTotal)
    #return(bothTotal)

def divConMaxSub(self, array, first, last):

    if (last-first) == 0: 
      return array[first: last +1], array[0]


    center = (first+last)// 2
    #Recursive calls to divConMaxSub
    (minA, maxA, sumA) = self.divConMaxSub(array, first, center)
    (minB, maxB, sumB) = self.divConMaxSub(array, center+1, last)
    #call to get max cross values
    (maxL, maxR, maxCross) = divConHelper(array, first, center, last)

    #Calulate the max subarray value
    finalMax = max(sumA, sumB, maxCross)
    #Logic block for return values
    if (finalMax == sumA):
      return array[minA: maxA], sumA
      #return minA, maxA, sumA
    elif (finalMax == sumB):
      return array[minB: maxB], sumB
      #return minB, maxB, sumB
    elif (finalMax == maxCross):
      return array[maxL: maxR], maxCross
      #return maxL, maxR, maxCross

Answer 1

本声明：

return array[minA: maxA], sumA

不会返回三个参数（正如您在此代码中所期望的那样）：

(minA, maxA, sumA) = self.divConMaxSub(array, first, center)

它返回一个数组的块作为第一个参数，sum作为第二个参数。因此，Python抱怨说它不能使用divConMaxSub的输出来初始化左边的三个值，因为右边只有两个值可用。

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1 个答案: