Submission #519429

#	Time	Username	Problem	Language	Result	Execution time	Memory
519429		Jomnoi	Lasers (NOI19_lasers)	C++17	100 / 100	220 ms	68500 KiB

lasers

#include <bits/stdc++.h>
#define DEBUG 0
using namespace std;
using pii = pair <int, int>;

const int N = 5e5+10;
vector <int> laser[N];
vector <int> qs[N];
int ct[N];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int l, r;
    cin >> l >> r;
    for(int i = 1; i <= r; i++) {
        int x, y;
        cin >> x;
        while(x--) {
            cin >> y;
            laser[i].push_back(y);
        }
        qs[i].push_back(0);
        for(int j = 0; j < laser[i].size(); j++) {
            qs[i].push_back(qs[i].back()+laser[i][j]);
        }
        if(DEBUG) {
            cout << "\nDebug : ";
            for(auto v : qs[i]) {
                cout << v << " ";
            }
            cout << endl << endl;
        }
    }
    if(DEBUG) {
        cout << endl;
    }
    vector <pii> vec;
    for(int i = 1; i <= r; i++) {
        for(int j = 0; j < laser[i].size(); j++) {
            int left = qs[i][j];
            int right = l-qs[i].back()+qs[i][j+1];
            int range = right-left;
            if(DEBUG) {
                cout << "Debug : ";
                cout << left << " " << right << " " << 2*laser[i][j]-range << " " << range-laser[i][j] << endl;
            }
            if(2*laser[i][j]-range > 0) {
                vec.emplace_back(left+range-laser[i][j]+1, 1);
                vec.emplace_back(right-range+laser[i][j]+1, -1);
            }
        }
        if(DEBUG) {
            cout << endl;
        }
    }
    sort(vec.begin(), vec.end());
    int ans = 0, sum = 0, left = -1;
    for(auto v : vec) {
        sum += v.second;
        if(left == -1) {
            left = v.first;
        }
        if(!sum) {
            ans += v.first-left;
            left = -1;
        }
    }
    cout << ans;
    return 0;
}

Compilation message (stderr)

lasers.cpp: In function 'int main()':
lasers.cpp:24:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |         for(int j = 0; j < laser[i].size(); j++) {
      |                        ~~^~~~~~~~~~~~~~~~~
lasers.cpp:40:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |         for(int j = 0; j < laser[i].size(); j++) {
      |                        ~~^~~~~~~~~~~~~~~~~

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