Submission #1063377

#	Time	Username	Problem	Language	Result	Execution time	Memory
1063377		CodeLakVN	Lasers (NOI19_lasers)	C++17	100 / 100	82 ms	33396 KiB

lasers

#include <bits/stdc++.h>

#define no "NO"
#define yes "YES"
#define F first
#define S second
#define vec vector
#define task "LASERS"
#define ll long long
#define _mp make_pair
#define ii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define evoid(val) return void(std::cout << val)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)
#define unq(x) sort(all(x)); x.resize(unique(all(x)) - x.begin())

using namespace std;

template<typename U, typename V> bool maximize(U &a, V b) {
    if (a < b) { a = b; return 1; } return 0;
}
template<typename U, typename V> bool minimize(U &a, V b) {
    if (a > b) { a = b; return 1; } return 0;
}

const int N = (int)2e5 + 9;
const int INF = (int)1e9;
const int MOD = (int)1e9 + 7;

int len, numRow;
vector<vector<int>> rows;

namespace sub1 {
    bool valid() {
        return numRow == 1 && rows[1][0] == 1;
    }

    void solve() {
        if (rows[1][1] <= len / 2) cout << 0 << "\n";
        else cout << rows[1][1] - (len - rows[1][1] + 1) + 1 << "\n";
    }
}

namespace sub2 {
    bool valid() {
        FOR(i, 1, numRow) if (rows[i][0] != 1) return false;
        return true;
    }

    void solve() {
        int maxWidth = 0;
        FOR(i, 1, numRow) maximize(maxWidth, rows[i][1]);
        if (maxWidth <= len / 2) cout << 0 << "\n";
        else cout << maxWidth - (len - maxWidth+ 1) + 1 << "\n";
    }
}

namespace sub34 {
    bool valid() {
        int sumX = 0;
        FOR(i, 1, numRow) sumX += rows[i][0];
        return ((numRow == 2 && len <= (int)1e6) || (len <= (int)1e3 && sumX <= (int)1e3));
    }

    void solve() {
        vector<vector<int>> sum;
        FOR(i, 1, numRow) {
            vector<int> curSum(rows[i][0] + 1, 0);
            FOR(j, 1, rows[i][0]) curSum[j] = curSum[j - 1] + rows[i][j];
            sum.push_back(curSum);
        }

        int ans = len;
        FOR(i, 1, len) {
            bool ok = 1;
            FOR(id, 0, numRow - 1) {
                int pos = lower_bound(sum[id].begin(), sum[id].end(), i) - sum[id].begin();
                if (pos > rows[id + 1][0]) continue;
                pos--;
                if (sum[id][rows[id + 1][0]] - sum[id][pos] >= len - i + 1) {
                    ok = 0;
                    break;
                }
            }
            if (ok) ans--;
        }
        cout << ans << "\n";
    }
}

namespace subFull {
    vector<ii> events;
    int sum[N];

    void solve() {
        FOR(i, 1, numRow) {
            sum[0] = 0;
            FOR(j, 1, rows[i][0]) sum[j] = sum[j - 1] + rows[i][j];
            FOR(j, 1, rows[i][0]) {
                int val = rows[i][j];
                int L = sum[j - 1] + 1, R = len - (sum[rows[i][0]] - sum[j]);

                if (L + val - 1 < R - val + 1) continue;

                events.push_back({R - val + 1, 1});
                events.push_back({L + val, -1});
            }
        }

        sort(events.begin(), events.end());
        int ans = 0, sum = 0, curL = -1;
        for (auto [u, v] : events) {
            sum += v;
            if (curL == -1) curL = u;
            if (sum == 0) {
                ans += u - curL;
                curL = -1;
            }
        }
        cout << ans << "\n";
    }
}

void main_code() {
    cin >> len >> numRow;
    rows.resize(numRow + 1);
    FOR(i, 1, numRow) {
        int n;
        cin >> n;
        rows[i].push_back(n);
        FOR(j, 1, n) {
            int x;
            cin >> x;
            rows[i].push_back(x);
        }
    }

    if (sub1::valid()) sub1::solve();
    else if (sub2::valid()) sub2::solve();
    else if (sub34::valid()) sub34::solve();
    else subFull::solve();
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    const bool MULTITEST = 0;
    int num_test = 1; if (MULTITEST) cin >> num_test;
    while (num_test--) { main_code(); cout << "\n"; }
}

/* Lak lu theo dieu nhac */

Compilation message (stderr)

lasers.cpp: In function 'int main()':
lasers.cpp:149:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  149 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
lasers.cpp:150:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  150 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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