Submission #642229

#	Time	Username	Problem	Language	Result	Execution time	Memory
642229		makanhulia	Lasers (NOI19_lasers)	C++17	10 / 100	28 ms	2912 KiB

lasers

#include <bits/stdc++.h>

using namespace std;

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    int l, r; cin >> l >> r;
    vector<pair<int, int>>seg;

    for(int i = 1; i <= r; i++){
        int left = 0, right = l;
        int x; cin >> x;
        vector<int>v(x);
        for(int j = 0; j < x; j++){
            cin >> v[j];
            left += v[j];
        }
        left -= v.back();

        for(int j = x - 1; j >= 0; j--){
            int l1 = left, r1 = left + v[j];
            int l2 = right - v[j], r2 = right;
            if(max(l1, l2) < min(r1, r2)){
                seg.emplace_back(max(l1, l2), min(r1, r2));
            }
            if(j) left -= v[j - 1];
            right -= v[j];
        }
    }

    sort(seg.begin(), seg.end());

    int ans = 0;
    int left = 0, right = 0;
    int sz = seg.size();

    while(left < sz && right < sz){
        while(right + 1 < sz && seg[right + 1].first <= seg[right].second) right++;
        ans += (seg[right].second - seg[left].first);
        left = right + 1;
        right = left;
    }

    cout << ans << '\n';

    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 14
• Subtask 3: 0 / 20
• Subtask 4: 0 / 21
• Subtask 5: 0 / 22
• Subtask 6: 0 / 13