Типичная ситуация

// OK BS http://contest.uni-smr.ac.ru/ru/problemset/6137/

# include <iostream>
# include <vector>
using namespace std;

bool check(vector<int32_t> &m, int32_t mid, int32_t n) {
    vector<int32_t> cur(n, mid);
    for (size_t i = 0; i < n; i++) {
        int32_t m_i = m[i];
        if (i > 0 && cur[i - 1] != 0) {
            m_i -= min(cur[i - 1], m_i);
        }
        int32_t x = min(cur[i], m_i);
        cur[i] -= x;
        m_i -= x;
        if (i < n - 1) {
            x = min(cur[i + 1], m_i);
            cur[i + 1] -= x;
            m_i -= x;
        }
        if (m_i != 0) {
            return false;
        }
    }
    return true;
}

int main() {
    int32_t n;
    cin >> n;
    vector<int32_t> m(n);
    for (size_t i = 0; i < n; i++) {
        cin >> m[i];
    }
    int32_t left = 0;
    int32_t right = 1000000;
    while (right - left > 1) {
        int32_t mid = (left + right) / 2;
        if (check(m, mid, n)) {
            right = mid;
        }
        else {
            left = mid;
        }
    }
    cout << right;
    return 0;
}