Submission #1034403

#	Time	Username	Problem	Language	Result	Execution time	Memory
1034403		tvladm2009	Sparklers (JOI17_sparklers)	C++17	50 / 100	25 ms	1484 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];
__int128 y[N];
bool dp[N][N];

bool check(__int128 v) {
    for (int i = 1; i <= n; ++i) {
        y[i] = x[i] - 2 * v * t * i;
    }
    memset(dp, 0, sizeof(dp));
    dp[k][k] = 1;
    for (int h = 1; h <= n; ++h) {
        for (int l = 1; l + h - 1 <= n; ++l) {
            int r = l + h - 1;
            if (dp[l][r] == 0) continue;
            if (r < n && y[r + 1] <= y[l]) dp[l][r + 1] = 1;
            if (l > 1 && y[r] <= y[l - 1]) dp[l - 1][r] = 1;
        }
    }
    return dp[1][n];
}

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