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Submission #333489

# Submission time Handle Problem Language Result Execution time Memory
333489 2020-12-06T13:26:05 Z ncduy0303 Walking (NOI12_walking) C++17
25 / 25
 2 ms 1388 KB 
#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 l, n; 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] = {t + (double)l / v, i};
    }
    sort(tin.begin(), tin.end());
    sort(tout.rbegin(), tout.rend());
    int dp[n + 1][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 = 1;
    // cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case #" << t  << ": ";
        solve();
    }
}

Subtask #1
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 384 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct

Subtask #3
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 512 KB Output is correct
2 Correct 1 ms 620 KB Output is correct
3 Correct 1 ms 492 KB Output is correct
4 Correct 1 ms 620 KB Output is correct

Subtask #4
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 748 KB Output is correct
2 Correct 2 ms 896 KB Output is correct
3 Correct 1 ms 876 KB Output is correct
4 Correct 1 ms 748 KB Output is correct

Subtask #5
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 1388 KB Output is correct
2 Correct 2 ms 1004 KB Output is correct
3 Correct 2 ms 1132 KB Output is correct
4 Correct 2 ms 1004 KB Output is correct