Submission #336423

#	Time	Username	Problem	Language	Result	Execution time	Memory
336423		ncduy0303	Lasers (NOI19_lasers)	C++17	100 / 100	149 ms	10076 KiB

lasers

#include <bits/stdc++.h>

using namespace std;

#define ar array
#define ll long long

const int MAX_N = 1e5 + 1;
const int MOD = 1e9 + 7;
const int INF = 1e9;
const ll LINF = 1e18;



void solve() {
    int len, n; cin >> len >> n;
    vector<ar<int,2>> block; // all ranges where the laser cannot pass through
    for (int i = 0; i < n; i++) {
        int m; cin >> m;
        vector<int> ps(m + 1);
        for (int i = 1; i <= m; i++) {
            cin >> ps[i];
            ps[i] += ps[i - 1];
        }
        for (int i = 1; i <= m; i++) {
            int l = len - (ps[m] - ps[i - 1]) + 1;
            int r = ps[i];
            if (l <= r) block.push_back({l, r});
        }
    }
    sort(block.begin(), block.end());
    if (block.empty()) {
        cout << 0 << "\n";
        return;
    }
    int ans = 0;
    auto rng = block[0];
    for (int i = 1; i < block.size(); i++) {
        auto new_rng = block[i];
        if (rng[1] + 1 < new_rng[0]) {
            ans += rng[1] - rng[0] + 1;
            rng = new_rng;
        }
        else {
            rng[1] = max(rng[1], new_rng[1]);
        }
    }
    ans += rng[1] - rng[0] + 1;
    cout << ans << "\n";
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);

    int tc = 1;
    // cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case #" << t  << ": ";
        solve();
    }
}

Compilation message (stderr)

lasers.cpp: In function 'void solve()':
lasers.cpp:38:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |     for (int i = 1; i < block.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~

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