暑假集训7月20日（距离结训赛26天）

K - Subarrays OR

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int>pii;
const int N=1e5+10;
int n;
set<ll> preans,nowans,ans;
signed main()
{
    int t;
    cin>>t;
    while(t--)
    {
        ans.clear();
        preans.clear();
        cin>>n;
        for (int i=1; i<=n; i++)
        {
            ll x;
            cin>>x;
            nowans.clear();
            nowans.insert(x);
            ans.insert(x);
            for (auto y:preans)
            {
                nowans.insert(x|y);
                ans.insert(x|y);
            }
            preans=nowans;
        }
        cout<<ans.size()<<"\n";
    }
    return 0;
}

最近在搞DFS，虽然DFS暴搜不能过，但是调出来就不错了，卑微

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int>pii;
const int N=1e5+10;
unordered_map<ll,bool>mp;
ll a[N];
int n;
void dfs(int u,ll num,int backpos)
{
    if (!backpos)
    {
        return;
    }
    if (backpos)
    {
        num=num|a[u];
        mp[num]=1;
        backpos--;
        dfs(u+1,num,backpos);
    }
}
signed main()
{
    int t;
    cin>>t;
    while(t--)
    {
        mp.clear();
        cin>>n;
        for (int i=1; i<=n; i++)
            cin>>a[i];
        for (int i=1; i<=n; i++)
        {
            int backpos=n-i+1;
            dfs(i,a[i],backpos);
        }
        cout<<mp.size()<<"\n";
    }
    return 0;
}

标签：26,20,int,nowans,num,结训,ans,ll,backpos
来源： https://www.cnblogs.com/Mercury1988/p/16496914.html