Submission #89495

#	Time	Username	Problem	Language	Result	Execution time	Memory
89495		win11905	Walking (NOI12_walking)	C++11	25 / 25	4 ms	1012 KiB

walking

/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author win11905
 */

#include <bits/stdc++.h>
#define all(x) (x).begin(), (x).end()
#define long long long
#define pii pair<int, int>
#define x first
#define y second
using namespace std;
const long MOD = 1e9+7, LINF = 1e18 + 1e16;
const int INF = 1e9+1;
const double EPS = 1e-10;
const int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};

const int N = 505;

class walking {
private:
    int n, l;
    int dp[N];
    vector<pii> vec;
    bool check(int a, int b) {
        if(vec[a].x >= vec[b].x) return false;
        return l * vec[b].y + vec[a].x * vec[a].y * vec[b].y > l * vec[a].y + vec[b].x * vec[b].y * vec[a].y;
    }
public:
    void solve(istream& cin, ostream& cout) {
        cin >> l >> n;
        for(int i = 0, a, b; i < n; ++i) cin >> a >> b, vec.emplace_back(a, b);
        sort(all(vec));
        for(int i = n-1; ~i; --i) {
            dp[i] = 1;
            for(int j = i+1; j < n; ++j) if(check(i, j)) dp[i] = max(dp[i], dp[j] + 1);
        }
        cout << *max_element(dp, dp+n);
    }
};

class Solver {
public:
    void solve(std::istream& in, std::ostream& out) {
        walking *obj = new walking();
        obj->solve(in, out);
    }
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    Solver solver;
    std::istream& in(std::cin);
    std::ostream& out(std::cout);
    solver.solve(in, out);
    return 0;
}

• Subtask 1: 3 / 3
• Subtask 2: 3 / 3
• Subtask 3: 5 / 5
• Subtask 4: 7 / 7
• Subtask 5: 7 / 7