201006-2稀疏向量

试题编号	202006-2
试题名称	稀疏向量
时间限制	2.0s
内存限制	512.0MB

#include<iostream>

using namespace std;

int main()
{
	int n, a, b,index,value;
	long long int out=0;
	int aa[100] = {0}, bb[100] = {0};
	cin >> n >> a >> b;
	for (int i = 1; i <=a; i++)
	{
		cin >> index >> value;
		aa[index] = value;
	}
	for (int i = 1; i <= b; i++)
	{
		cin >> index >> value;
		bb[index] = value;
	}
	for (int i = 1; i <= n; i++)
	{
		if (aa[i] != 0 && bb[i] != 0)
			out += aa[i] * bb[i];
	}
	cout << out << endl;
	return 0;
}

#include<vector>
using namespace std;

int n;
int a, b;
long long ans;//使用long long

vector<pair<int, int>> u, v;
int main()
{
	scanf("%d%d%d", &n, &a, &b);
	int id, val;
	for (int i = 0; i < a; i++)
	{
		scanf("%d%d", &id, &val);
		u.push_back({ id, val });
	}
	for (int i = 0; i < b; i++)
	{
		scanf("%d%d", &id, &val);
		v.push_back({ id, val });
	}
	int i = 0, j = 0;
	while (i < a&&j < b)
	{
		if (u[i].first == v[j].first)//.first存的是id,.second存的是val
		{
			ans += u[i].second*v[j].second;
			i++, j++;
		}
		else if (u[i].first > v[j].first){
			j++;
		}
		else{
			i++;
		}
	}
	printf("%lld\n", ans);
	return 0;
}