为什么向量对的problemsPathCoordinate向量是空的？

Question

我曾尝试用成对向量的较大向量中的一些内容填充成对向量的较小向量，但没有成功。下面是couts的相关代码及其输出。希望这是足够详细的。

    /*******************Problems Occur*****************/

        int iFirst=problemsStartAt;//first index to copy
        int iLast=problemsEndAt-1;//last index -1, 11th stays
        int iLen=iLast-iFirst;//10-8=2
        //if(problemsStartAt!=0)//I.a
        if(problemsStartAt!=0&&problemsEndAt!=0)//I.b
        {
            v_problem_temp=allPathCoordinates[problemsStartAt];
            cout<<"266:"<<v_problem_temp.size()<<endl;
            cout<<"267:"<<allPathCoordinates.at(1).size()<<endl;
            for(vector<pair<int,int>>::iterator  it2=v_problem_temp.begin();
            it2!=v_problem_temp.end();
            ++it2)
                {
                    apair=*it2;
                    point[apair.first][apair.second]=Yellow;
                    cout<<apair.first<<","<<apair.second<<endl;
                }
                problemsPathCoordinate.resize(iLen);
                cout<<"iLen*sizeof(problemsPathCoordinate):"      <<iLen*sizeof(problemsPathCoordinate)<<endl;


                    memcpy(&problemsPathCoordinate[0],&allPathCoordinates[iFirst],iLen*sizeof(problemsPathCoordinate));
        cout<<"279:problemsPathCoordinate.size():"<<problemsPathCoordinate.size()<<endl;

        problemsPathCoordinate.resize(iLen);
        memcpy(&problemsPathCoordinate[0],&allPathCoordinates[iFirst],iLen*sizeof(problemsPathCoordinate));
        cout<<"283:problemsPathCoordinate.size():"<<problemsPathCoordinate[0].size()<<endl;
        cout<<"284:problemsPathCoordinate.size():"<<problemsPathCoordinate[1].size()<<endl;

        cout<<"286:allPathCoordinates.size():"<<allPathCoordinates.size()<<endl;
        cout<<"287:allPathCoordinates.size():"<<allPathCoordinates.size()<<endl;
        //from http://stackoverflow.com/questions/35265577/c-reverse-a-smaller-range-in-a-vector


}
    Output:
    759: path NOT full-filled, number: 8
    755: Problems START here at:8
    759: path NOT full-filled, number: 9
    700: Problems END here at: 11
    266:0
    267:0
    iLen*sizeof(problemsPathCoordinate):72
    279:problemsPathCoordinate.size():3
    283:problemsPathCoordinate.size():0
    284:problemsPathCoordinate.size():0
    286:allPathCoordinates.size():79512
    287:allPathCoordinates.size():79512
    time:39 seconds

为什么三个problemsPathCoordinate元素是空的。如何修复它？Bo

Answer 1

for (向量>>：：迭代器it = allPathCoordinates.begin()；it != allPathCoordinates.end()；++it) { allPathCoordinates.erase(allPathCoordinates.begin()+5，allPathCoordinates.end()-2)；v_temp = *it；//cout<<"v_temp.size():"<

    for (vector<pair<int,int> >::iterator it2 = v_temp.begin(); it2 != v_temp.end(); ++it2) {
        //v_temp.erase(v_temp.begin()+2);
        apair = *it2;
        //cout << "(" << apair.first << "," << apair.second << ") ; ";
        openPoints[apair.first][apair.second]=0;
        closedPoints[apair.first][apair.second]=1;
        allObstacles[apair.first][apair.second]=Wall;
        point[apair.first][apair.second]=Yellow;
    }
    /