Submission #1274787

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274787		sakka	Global Warming (CEOI18_glo)	C++20	62 / 100	37 ms	6228 KiB

glo

#include<bits/stdc++.h>
#define ll long long
#define fi first
#define sec second
#define pb push_back
#define pint pair<long long, long long>
using namespace std;
void freop(){
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
}
const ll INF = 1e18, mod = 1e9+7;
ll n, x;
vector<ll>vec(2e5+2);

void solve(){
    cin >> n >> x;
    for(int i=1; i<=n; i++){
        cin >> vec[i];
    }

    vector<ll> lis;
    vector<ll> sme(n+1), sz(n+1);
    ll mxsz = 0, ans = 0;

    for(int i=n; i>=1; i--){
        if(!lis.size()){
            lis.pb(-vec[i]);
        }
        else{
            auto it = lower_bound(lis.begin(), lis.end(), -vec[i]) - lis.begin();
            if(it == lis.size()) lis.pb(-vec[i]);
            else lis[it] = -vec[i];
        }

        mxsz = max(mxsz, (ll)lis.size());
        sme[i] = -lis[lis.size()-1];
        sz[i] = lis.size();
    }

    mxsz = 0; lis.clear();

    for(int i=1; i<=n; i++){
        vec[i] -= x;
        if(!lis.size()){
            lis.pb(vec[i]);
        }
        else{
            auto it = lower_bound(lis.begin(), lis.end(), vec[i]) - lis.begin();
            if(it == lis.size()) lis.pb(vec[i]);
            else lis[it] = vec[i];
        }

        if(lis.size() > mxsz){
            mxsz = lis.size();
        }

        if(i < n){
            auto it = lower_bound(lis.begin(), lis.end(), sme[i+1]) - lis.begin();
            ans = max(ans, sz[i+1] + it);
        }
        else ans = max(ans, (ll)lis.size());

        // cout << i << " " << lis.size() << " " << sz[i+1] << endl;
    }

    cout << ans << endl;

}

int main(){
    ios_base :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
    // freop();
    solve();
}   

Compilation message (stderr)

glo.cpp: In function 'void freop()':
glo.cpp:9:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    9 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
glo.cpp:10:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 0 / 13
• Subtask 4: 10 / 10
• Subtask 5: 20 / 20
• Subtask 6: 17 / 17
• Subtask 7: 0 / 25