Submission #991912

#	Time	Username	Problem	Language	Result	Execution time	Memory
991912		crafticat	Global Warming (CEOI18_glo)	C++17	100 / 100	94 ms	10068 KiB

glo

#include <bits/stdc++.h>

using namespace std;
using pii = pair<int,int>;

vector<int> lis(vector<int> &arr, int constX) {
    vector<int> dp(arr.size());
    set<pii> s;
    for (int i = 0; i < arr.size();i++) {
        int v = arr[i];
        if (constX >= 0) {
            auto it = s.lower_bound({v, 0});
            if (s.empty()) dp[i] = 0;
            else {
                it = s.lower_bound({v + constX, 0});
                bool remOld = false;
                if (it != s.begin()) it--;
                else remOld = true;
                dp[i] = it->second - (remOld);
            }
        }

        if (s.empty()) {
            s.insert({v,1});
        }

        auto it = s.lower_bound({v,0});
        bool remOld = true;
        if (it == s.end()) {
            it--;
            remOld = false;
        }
        int p = it->second;
        if (it->first > v || !remOld) {
            if (remOld) s.erase(it);
            s.emplace(v,p + (!remOld));
        }


        if (constX == -1)
            dp[i] = p + !remOld;
    }

    return dp;
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(nullptr);

    int n, x; cin >> n >> x;
    vector<int> arr(n), revArr(n);
    for (int i = 0; i < n; ++i) {
        cin >> arr[i];
        revArr[i] = -arr[i];
    }
    std::reverse(revArr.begin(), revArr.end());
    auto before = lis(arr,-1), after = lis(revArr,x);
    int ans = 0;
    for (int i = 0; i < n; ++i) {
        ans = max(ans, before[i] + after[n - 1 - i]);
        if (ans == 3) {
            int stop = 25;
        }
    }
    cout << ans;

    return 0;
}

Compilation message (stderr)

glo.cpp: In function 'std::vector<int> lis(std::vector<int>&, int)':
glo.cpp:9:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |     for (int i = 0; i < arr.size();i++) {
      |                     ~~^~~~~~~~~~~~
glo.cpp: In function 'int main()':
glo.cpp:62:17: warning: unused variable 'stop' [-Wunused-variable]
   62 |             int stop = 25;
      |                 ^~~~

• 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