c++ - 将元组 vector 构造成堆

Question

从here，我能够将元组的 vector 转换为堆。
但是，我想更进一步地从头开始构造元组，而无需转换 vector 。
我以前如何构造 vector 的方法如下:

vector<tuple<int,int,int>> x;
for (int ii=0; ii < 10; ii++){
    for (int jj=0; jj < 10; jj++){
        y[0] = ii + rand() % 10;
        y[1] = jj + rand() % 10;
        y[2] = rand() % 100;
        x.emplace_back(y[0], y[1], y[2]);
    }
}

我如何尝试从头开始构建堆

struct Comp { 
    bool operator()(const tuple<int,int,int>& a, 
            const tuple<int,int,int>& b){
           return (get<2>(a) < get<2>(b)); 
    }
};

vector<tuple<int,int,int>> x;

for (int ii=0; ii < 10; ii++){
    for (int jj=0; jj < 10; jj++){
        y[0] = ii + rand() % 10;
        y[1] = jj + rand() % 10;
        y[2] = rand() % 100;
        x.emplace_back(y[0], y[1], y[2]);
        push_heap(x.begin(), x.end(), Comp()); // using push_heap
    }
}

push_heap()行上的错误:

Severity    Code    Description Project File    Line    Suppression State
Error   C2228   left of '.begin' must have class/struct/union
Error (active)  E0153   expression must have class type
Error (active)  E0153   expression must have class type
Error   C2780   'void std::push_heap(_RanIt,_RanIt,_Pr)': expects 3 arguments - 2 provided
Error   C2672   'push_heap': no matching overloaded function found

Answer 1

您正在使用x作为堆和元组的名称。再加上operator[]并不是访问元组字段的方法。另外，您尝试多次创建堆
我想你的意思是这样的

for (int ii=0; ii < 10; ii++){
    for (int jj=0; jj < 10; jj++){
        tuple<int,int,int> y;
        get<0>(y) = ii + rand() % 10;
        get<1>(y) = jj + rand() % 10;
        get<2>(y) = rand() % 100;
        x.emplace_back(y);
    }
}
push_heap(x.begin(), x.end(), Comp()); // using push_heap

甚至更简单

for (int ii=0; ii < 10; ii++){
    for (int jj=0; jj < 10; jj++){
        x.emplace_back(ii + rand() % 10, jj + rand() % 10, rand() % 100);
    }
}
push_heap(x.begin(), x.end(), Comp()); // using push_heap