Submission #367216

#	Time	Username	Problem	Language	Result	Execution time	Memory
367216		leu_naut	Global Warming (CEOI18_glo)	C++11	100 / 100	136 ms	7028 KiB

glo

#include <bits/stdc++.h>
#define ll long long

using namespace std;

ll n, x, v[200005], dp[200005];

int main()
{
    cin >> n >> x;
    for (int i = 0; i < n; i++)
        cin >> v[i];
    vector<ll> lis(n, INT_MAX);
    ll k = 0;
    // longest increasing subsequence ending at i
    for(int i = 0; i < n; i++)
    {
        int j = lower_bound(lis.begin(), lis.end(), v[i])-lis.begin();
        lis[j] = v[i];
        dp[i] = j+1;
        k = max(k, dp[i]);
    }
    lis.assign(n,INT_MAX);
    // longest decreasing subsequence ending at i of reverse
    // = longest increasing subsequence starting at i
    for(int i = n-1; i >= 0; i--)
    {
        int j = lower_bound(lis.begin(), lis.end(), -v[i]+x)-lis.begin();
        int jj = lower_bound(lis.begin(), lis.end(), -v[i])-lis.begin();
        lis[jj] = -v[i];
        k = max(k, dp[i]+j);
    }
    cout << k << endl;
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 13 / 13
• Subtask 4: 10 / 10
• Subtask 5: 20 / 20
• Subtask 6: 17 / 17
• Subtask 7: 25 / 25