Submission #743081

#	Time	Username	Problem	Language	Result	Execution time	Memory
743081		vjudge1	Lasers (NOI19_lasers)	C++17	100 / 100	193 ms	13800 KiB

lasers

#include <bits/stdc++.h>
using namespace std;
using pi = pair<int,int>;

int l,r,in,n,ans=0;
int qs[500005]={};
vector<pi> ep;

int main()
{
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> l >> r;
    qs[0]=0;
    for(int i=0;i<r;i++){
        cin >> n;
        for(int j=1;j<=n;j++){
            cin >> qs[j];
            qs[j]+=qs[j-1];
        }
        //qs[n+1]=qs[n];
        for(int j=1;j<=n;j++){
            //gen ep
            int sp=qs[j-1],sn=qs[n]-qs[j],val=qs[j]-qs[j-1];
            int L=val,M=l-sn-sp;
            //cout << '=' << L << ' ' << M << endl;
            if(M-L+1 > L)continue;
            ep.push_back({M-L+1+sp,1});
            ep.push_back({L+1+sp,-1});
        }
    }
    sort(ep.begin(),ep.end());
    ep.push_back({l,-9999});
    int block=0;
    for(int i=0,j=ep.size()-1;i<j;i++){
        auto[indx,v]=ep[i];
        //cout << indx << ' ' << v << ' ' << endl;
        block+=v;
        if(block>=1 && (ep[i+1]).first > indx){
            ans+=((ep[i+1]).first - indx);
        }
    }
    cout << ans;
    return 0;
}
/*
11 3
2 2 3
1 7
2 4 1
*/

• Subtask 1: 10 / 10
• Subtask 2: 14 / 14
• Subtask 3: 20 / 20
• Subtask 4: 21 / 21
• Subtask 5: 22 / 22
• Subtask 6: 13 / 13