Submission #689430

#	Time	Username	Problem	Language	Result	Execution time	Memory
689430		Matteo_Verz	Bigger segments (IZhO19_segments)	C++17	73 / 100	84 ms	12068 KiB

segments

#include <bits/stdc++.h>
#ifdef BLAT
    #include "debug/debug.hpp"
#else
    #define debug(x...)
#endif

using namespace std;

const long long INF = 1'000'000'000'000'000; // 1e15

int binSearch(const vector <long long> &v, long long val) {
    int r, pas;
    for (r = -1, pas = 1 << 17; pas; pas >>= 1)
        if (r + pas < v.size() && v[r + pas] < val)
            r += pas;
    r++;

    return r;
}

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

    vector <int> v(1 + n), dp(1 + n);
    vector <long long> sp(1 + n), s(1 + n, INF);

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

    dp[1] = 1;
    s[1] = sp[1];
    for (int i = 1; i <= n; i++) {
        dp[i] = max(dp[i], dp[i - 1]);
        s[i] = min(s[i], s[i - 1] + v[i]);

        int pos = binSearch(sp, s[i] + sp[i]);
        if (pos == n + 1) continue;

        if (dp[pos] == dp[i] + 1)
            s[pos] = min(s[pos], sp[pos] - sp[i]);
        else if (dp[pos] < dp[i] + 1) {
            s[pos] = sp[pos] - sp[i];
            dp[pos] = 1 + dp[i];
        }
    }

    cout << dp[n] << '\n';
    return 0;
}

Compilation message (stderr)

segments.cpp: In function 'int binSearch(const std::vector<long long int>&, long long int)':
segments.cpp:15:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |         if (r + pas < v.size() && v[r + pas] < val)
      |             ~~~~~~~~^~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 36 / 36
• Subtask 5: 0 / 27