Submission #1284783

#	Time	Username	Problem	Language	Result	Execution time	Memory
1284783		celes	Global Warming (CEOI18_glo)	C++20	100 / 100	85 ms	5452 KiB

glo

#include <bits/stdc++.h>
using namespace std;
#define     ll long long
#define    pll pair<ll, ll>
#define    pii pair<int, int>
#define     fi first
#define     se second
#define     pb push_back
#define     all(v) (v).begin(), (v).end()
#define     Unique(v) sort(all(v)); (v).erase(unique(all(v)), (v).end())

const int N = 3e5 + 5;

int n, x;
int a[N], c[N], val[N];
vector<int> b;
int fenpre[N], fensuf[N];

void update(int bit[], int u, int val) {
    while (u < N) {
        bit[u] = max(bit[u], val);
        u += u & -u;
    }
}

int get(int bit[], int u) {
    int res = 0;
    while (u) {
        res = max(res, bit[u]);
        u -= u & -u;
    }
    return res;
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    #define task "bseq"
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".ans", "w", stdout);
    }
    if (fopen("task.inp", "r")) {
        freopen("task.inp", "r", stdin);
        freopen("task.ans", "w", stdout);
    }
    cin >> n >> x;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        c[i] = a[i];
        b.pb(a[i]);
    }

    b.pb(0);
    Unique(b);
    for (int i = 1; i <= n; i++)
        a[i] = lower_bound(all(b), a[i]) - b.begin();

    for (int i = 1; i <= n; i++) {
        ll p = get(fenpre, a[i] - 1) + 1;
        val[i] = p;
        update(fenpre, a[i], p);
    }

    int res = 0;

    for (int i = n; i >= 1; i--) {
        int p = get(fensuf, N - 3 - a[i] - 1) + 1;

        int low = max(0, c[i] - x);
        int idx = upper_bound(all(b), low) - b.begin() - 1;

        res = max(res, val[i] + get(fensuf, N - 3 - idx - 1));

        update(fensuf, N - 3 - a[i], p);
    }

    cout<<res;

    cerr<<setprecision(3)<<fixed<<"Time elapsed: "<< 1.0 * clock() / CLOCKS_PER_SEC <<"s\n";
}

Compilation message (stderr)

glo.cpp: In function 'int main()':
glo.cpp:40:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
glo.cpp:41:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |         freopen(task".ans", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
glo.cpp:44:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |         freopen("task.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
glo.cpp:45:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |         freopen("task.ans", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• 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