Submission #522052

#	Time	Username	Problem	Language	Result	Execution time	Memory
522052		macktvz	Global Warming (CEOI18_glo)	C++17	10 / 100	163 ms	5140 KiB

glo

#include <bits/stdc++.h>
using namespace std;

template<class T> struct Seg { // comb(ID,b) = b
	const T ID = 0; T comb(T a, T b) { return max(a,b); }
	int n; vector<T> seg;
	void init(int _n) { n = _n; seg.assign(2*n,ID); }
	void pull(int p) { seg[p] = comb(seg[2*p],seg[2*p+1]); }
	void upd(int p, T val) { // set val at position p
		seg[p += n] = val; for (p /= 2; p; p /= 2) pull(p); }
	T query(int l, int r) {	// min on interval [l, r]
        if (l > r) return 0;
		T ra = ID, rb = ID;
		for (l += n, r += n+1; l < r; l /= 2, r /= 2) {
			if (l&1) ra = comb(ra,seg[l++]);
			if (r&1) rb = comb(seg[--r],rb);
		}
		return comb(ra,rb);
	}
};

Seg<int> st;


int main() {
    ios::sync_with_stdio(false);
	cin.tie(0),cout.tie(0);
    int n,k; cin >> n >> k;
    st.init(n+1);
    vector<int> A(n); for(auto &a : A) cin >> a;
    vector<int> X; for(int i : A) X.push_back(i);
    sort(begin(X),end(X));
    X.erase(unique(begin(X),end(X)),end(X));
    auto index = [&] (int x) {
        return (int)(lower_bound(begin(X),end(X),x) - begin(X));
    };
    // find lds in reverse array to have lis starting at index i
    vector<int> dp(n,0);
    reverse(begin(A),end(A));
    vector<int> lis;
    for(int i = 0; i < n; i++) {
        int pos = lower_bound(begin(lis),end(lis),-A[i]) - begin(lis);
        dp[i] = pos+1;
        if (pos == lis.size()) lis.push_back(-A[i]);
        else lis[pos]=-A[i];
    }
    reverse(begin(A),end(A));
    reverse(begin(dp),end(dp));
    int ans = 0;
    for(int i = 0; i < n; i++) {
        // check if we can get longer sequence
        ans = max(ans,dp[i] + st.query(index(A[i])+2,index(A[i] + k-1)+1));
        st.upd(index(A[i]) + 1, st.query(1,index(A[i]-1) + 1) + 1);
    }
    cout << ans << '\n';

}

Compilation message (stderr)

glo.cpp: In function 'int main()':
glo.cpp:44:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   44 |         if (pos == lis.size()) lis.push_back(-A[i]);
      |             ~~~~^~~~~~~~~~~~~

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