这是代码和错误消息，有什么想法吗？我试着在删除这行代码Building t = beginEndMap[b.id];后，编译就可以了。但无法找出这行代码对错误的偶然性。这一行与对无关，但编译错误与对有关。

错误消息，

Error:
required from 'std::pair<_T1, _T2>::pair(std::piecewise_construct_t, std::tuple<_Args1 ...>, std::tuple<_Args2 ...>) [with _Args1 = {const int&}; _Args2 = {}; _T1 = const int; _T2 = Building]'

源代码，

struct Building {
int id;
int pos;
int height;
bool isStart;
Building(int i, int p, int h, int s) {
id = i;
pos = p;
height = h;
isStart = s;
}
};
class Solution {
public:
vector<pair<int, int>> getSkyline(vector<vector<int>>& buildings) {
vector<Building> sortedBuilding;
unordered_map<int, Building> beginEndMap;
vector<pair<int, int>> result;
for (Building b : sortedBuilding) {
Building t = beginEndMap[b.id];
}
return result;
}
};
int main() {
}