Question

我试图将变量（1 - 100 000）长度向量分成随机部分以便进一步操作。但是我的代码崩溃了，到目前为止，我的调试没有结果。任何人都可以提供任何见解吗？

#include <math.h>
#include <vector>
#include <iostream>

using namespace std;

void subVectorize() {
//N ways to pick consecutive integer sequences of length M (M < N) K-Vlaue is Kth smallest number   in sequence
//Task: Find smallest possible subsequence

int M = rand() % (100000 - 1);

vector<int> nVector(M); //Vector to store sequence of variable length

for (int i = 0; i < nVector.size(); i++) //Populate the vector
{
    nVector[i] = i;
}

//Split the vector randomly

vector<int>::const_iterator start = nVector.begin() + (rand() % (100000 - 1));
vector<int>::const_iterator end = nVector.begin() + (rand() % (100000 - 1));
vector<int> subVector(start, end);

}

Answer 1

#include <cmath>
#include <vector>
#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std;

void subVectorize( )
{
    //N ways to pick consecutive integer sequences of length M (M < N) K-Vlaue is Kth smallest number   in sequence
    //Task: Find smallest possible subsequence

    int M;
    int randomEnd;
    int randomStart;

    M           = rand( ) % ( 100000 - 1 ) + 1;
    randomEnd   = rand( ) % ( M );

    if( randomEnd == 0 )
    {
        ++randomEnd;
    }

    randomStart = rand() % ( randomEnd );

    vector<int> nVector(M); //Vector to store sequence of variable length

    for ( unsigned int i = 0 ; i < nVector.size( ) ; i++ ) //Populate the vector
    {
        nVector[i] = i;
    }

    //Split the vector randomly

    vector<int>::const_iterator start   = nVector.begin() + randomStart;
    vector<int>::const_iterator end     = nVector.begin() + randomEnd;

    vector<int> subVector( start , end );

}

int main()
{
    srand( time( NULL ) );

    subVectorize( );

    return 0;
}

如果你这样调整它，它应该可以正常工作。

我已经包含了伪随机种子。

基本上您的问题是，start和end都可能超出范围而end可能在start之前，如果M为0则会出现问题？你不能创建一个大小为0的向量，你的代码无论如何都要访问它，这对于0 Vector来说是不行的。

rand( ) % ( 100000 - 1 ) + 1

+1是一个偏移量，这意味着它将是你的伪随机数+1，因此它不能为0.

试图对随机[1-100 000]长度的向量进行子向量化

1 个答案: