二维向量下标超出范围

Posted 2023-02-17

【中文标题】二维向量下标超出范围

【英文标题】：2D vector subscript out of range

【发布时间】：2014-02-11 02:32:07

【问题描述】：

实现if语句时表示向量下标超出范围。我想我在地板上添加了额外的 int，或者在 2D 向量中添加了额外的地板矢量。我正在使用 VS 2010(C++) 我试图在其他问题上找到它，但没有成功。

bool is_perfect_square(int);
    int main()
    
        int cust;
        vector<int>floor;
        vector<vector<int>>hotel;
        floor.push_back(0);
        hotel.push_back(floor);
        hotel[0][0]=1;
        for(cust=2; ; cust++)
        
            for(int i=0; i<=hotel.size(); i++)
            
                if(is_perfect_square(cust+hotel[i][floor.size()]))
                
                    floor.push_back(0);
                    hotel[i][cust]=cust;
                    break;
                
                else
                
                    hotel.push_back(floor);
                    hotel[hotel.size()][0]=cust;
                
            
        

        int sum=0;
            for(int a=1; a<=hotel.size(); a++)
            
                for(int b=1; b<=floor.size(); b++)
                
                    if(pow(a-1,2)+pow(b-1,2)==14234886498625)
                        sum+=hotel[a-1][b-1];
                
            



            cout<<sum<<endl;    
        system("pause");
        return 0;
    

    bool is_perfect_square(int n)
        
            int root=floor(sqrt(n));
            return n == root * root;
        

【问题讨论】：

你需要is_perfect_square函数中的“地板”吗？

另外，for(int i=0; i<=hotel.size(); i++) 无效，因为您正在访问下面的hotel[i]。下标范围仅从 0 到 hotel.size() - 1

【参考方案1】：

我把我的答案放在 cmets 中。

bool is_perfect_square(int);
int main()

    int cust;
    vector<int>floor;
    vector<vector<int>>hotel;
    floor.push_back(0);
    hotel.push_back(floor);
    hotel[0][0]=1;

    // you may not be able to get out of this loop 
    // because the "break" below only exits one level of the loop.
    for(cust=2; ; cust++)
    
        // this should be changed to "i<hotel.size()", 
        // because the subscript of a vector ranges from 0 to its size minus one.
        for(int i=0; i<=hotel.size(); i++)
        
            // here "floor.size()" should be floor.size() - 1, the same reason.
            if(is_perfect_square(cust+hotel[i][floor.size()]))
            
                floor.push_back(0);
                hotel[i][cust]=cust;
                break;
            
            else
            
                hotel.push_back(floor);
                hotel[hotel.size()][0]=cust;
            
        
    

    int sum=0;
        for(int a=1; a<=hotel.size(); a++)
        
            for(int b=1; b<=floor.size(); b++)
            
                if(pow(a-1,2)+pow(b-1,2)==14234886498625)
                    sum+=hotel[a-1][b-1];
            
        



        cout<<sum<<endl;    
    system("pause");
    return 0;


bool is_perfect_square(int n)
    
        int root=floor(sqrt(n));
        return n == root * root;