Submission #331714

#	Time	Username	Problem	Language	Result	Execution time	Memory
331714		ncduy0303	Walking (NOI12_walking)	C++17	25 / 25	2 ms	1388 KiB

walking

#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 n, l; cin >> l >> n;
    vector<pair<double,int>> tin(n), tout(n);
    for (int i = 0; i < n; i++) {
        int t, v; cin >> t >> v;
        tin[i] = {t, i};
        tout[i] = {(double)l / v + t, i};
    }
    sort(tin.begin(), tin.end());
    sort(tout.rbegin(), tout.rend());
    vector<vector<int>> dp(n + 1, vector<int>(n + 1));
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= n; j++)
            dp[i][j] = (tin[i - 1].second == tout[j - 1].second) ? dp[i - 1][j - 1] + 1 : max(dp[i - 1][j], dp[i][j - 1]);
    cout << dp[n][n] << "\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; tc = 1;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case #" << t  << ": ";
        solve();
    }
}

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