202006-2稀疏向量

#include 
using namespace std;
int main(){
	long long n, a, b, sum = 0;
	int x, y;
	cin >> n >> a >> b;
	map veca, vecb;
	for(int i = 0; i < a; i++){		
		cin >> x >> y;
		veca[x] = y;
	}
	for(int i = 0; i < b; i++){		
		cin >> x >> y;
		vecb[x] = y;
	}
	for(auto it = veca.begin(); it != veca.end(); it++){		
		if(vecb.find(it->first) != vecb.end())
			sum += vecb[it->first] * it->second;
	}
	cout << sum;
	return 0;
}

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