Submission #1017465

#	Time	Username	Problem	Language	Result	Execution time	Memory
1017465		vjudge1	Feast (NOI19_feast)	C++17	100 / 100	154 ms	12364 KiB

feast

#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
#define pb push_back
#define pf push_front
#define fi first
#define se second
const ll mod = 1e9+7, mxn = 3e5+7;
ll n, a[mxn], k;
pair<ll,ll> lmb(ll x)
{
    pair<ll,ll> dp[mxn][2];
    dp[1][0] = {0,0}; dp[1][1] = {a[1]-x,1};
    for (ll i = 2; i <= n; i++)
    {
        dp[i][0] = max(dp[i-1][0],dp[i-1][1]);
        dp[i][1] = max(make_pair(dp[i-1][0].fi+a[i]-x,dp[i-1][0].se+1),
                       make_pair(dp[i-1][1].fi+a[i],dp[i-1][1].se));
    }
    return max(dp[n][0],dp[n][1]);
}
void aliens()
{
    ll l = 0, r = 1e18, ans = -1;
    while (r >= l)
    {
        ll m = (r+l)>>1;
        pair<ll,ll> opt = lmb(m);
        if (opt.se <= k)
        {
            ans = max(ans,opt.fi+m*opt.se);
            r = m-1;
        }
        else l = m+1;
    }
    cout << ans;
}
signed main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    // freopen("test.inp","r",stdin); freopen("test.out","w",stdout); freopen("test.err","w",stderr);
    cin >> n >> k;
    for (ll i = 1; i <= n; i++) cin >> a[i];
    aliens();
}   

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 18 / 18
• Subtask 4: 10 / 10
• Subtask 5: 11 / 11
• Subtask 6: 20 / 20
• Subtask 7: 29 / 29