Submission #1029838

#	Time	Username	Problem	Language	Result	Execution time	Memory
1029838		tvladm2009	Sparklers (JOI17_sparklers)	C++17	50 / 100	69 ms	1476 KiB

sparklers

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
 
const int N = 1e3 + 5;
 
ll n, k, t;
ll x[N];
bool dp[N][N];
 
bool check(__int128 v) {
    memset(dp, 0, sizeof(dp));
    dp[1][n] = 1;
    for (int l = 1; l <= k; ++l) {
        for (int r = n; r >= k; --r) {
            if (l == 1 && r == n) continue;  
            if (l > 1 && dp[l - 1][r] == 1 && x[r] - x[l - 1] <= 2 * v * (r - l + 1) * t) {
                dp[l][r] = 1;
            }
            if (r < n && dp[l][r + 1] == 1 && x[r + 1] - x[l] <= 2 * v * (r - l + 1) * t) {
                dp[l][r] = 1;
            }
        }
    }
    return dp[k][k];
}
 
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> k >> t;
    for (int i = 1; i <= n; ++i) cin >> x[i];
    
    ll l = 0, r = 1e9, sol = -1;
    while (l <= r) {
        ll m = (l + r) / 2;
        if (check(m)) {
            sol = m;
            r = m - 1;
        } else {
            l = m + 1;
        }
    }
    cout << sol << "\n";
    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 20 / 20
• Subtask 3: 0 / 50