题解

用一个数记录标准值

#include<bits/stdc++.h>
#define int long long
using namespace std;

signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
    int n,b=0,q,m,x,y;
    cin >> n;
    map<int,int> mp;
    for (int i=1;i<=n;i++)
    {
    	cin >> x;
    	mp[i]=x;
	}
    cin >> q;
    while (q--)
    {
    	cin >> m;
		if (m==1)
		{
			cin >> x;
			b=x;
			mp.clear();
		}
		else if (m==2)
		{
			cin >> x >> y;
			mp[x]+=y;
		}
		else
		{
			cin >> y;
			cout << mp[y]+b << endl;
		}
	}
	return 0;
}