Submission #870021

#	Time	Username	Problem	Language	Result	Execution time	Memory
870021		Megumin2006	Growing Vegetables is Fun 4 (JOI21_ho_t1)	C++14	100 / 100	26 ms	12440 KiB

Main

#include <bits/stdc++.h>

#define int long long

using namespace std;

int n;

inline vector<int> get(vector<int> &a) {
    vector<int> r(n + 1), st, ans(n + 1);
    for(int i = n; i >= 1; --i) {
        while(st.size() && a[ st.back() ] > a[i]) st.pop_back();
        r[i] = st.size() ? st.back() : -1;
        st.push_back(i);
    }

    for(int i = 1; i <= n; ++i) {
        ans[i] += ans[i - 1];
        if (r[i] == -1) continue;
        ans[ r[i] ] += max(0ll, a[i] - a[ r[i] ] - ans[ r[i] ]  + 1);
    }

    return ans;
}

void solve() {
    cin >> n;
    vector<int> a(n + 1);

    for(int i = 1; i <= n; ++i) {
        cin >> a[i];
    }

    vector<int> ans1 = get(a);
    reverse(a.begin() + 1, a.end());
    vector<int> ans2 = get(a);
    reverse(ans2.begin() + 1, ans2.end());

    int ans = min(ans1[n], ans2[1]);
    for(int i = 1; i < n; ++i) {
        ans = min(ans, max(ans1[i], ans2[i]));
    }
    cout << ans;
}

signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    if (fopen("cf.inp", "r")) {
        freopen("cf.inp", "r", stdin);
        freopen("1.out", "w", stdout);
    }
    solve();
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:49:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |         freopen("cf.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Main.cpp:50:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |         freopen("1.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 40 / 40
• Subtask 2: 60 / 60