Submission #332335

#	Time	Username	Problem	Language	Result	Execution time	Memory
332335		alien_lover	Hacker (BOI15_hac)	C++14	0 / 100	1 ms	512 KiB

hac

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

typedef long long ll;

#define all(x) begin(x), end(x)
#define sz(x) (int) x.size()

const int PRIME = 1e9 + 7;

int n;
vector<int> prefSum;

// i1 inclusive, i2 exclusive
int getCumSum(int i1, int i2){
    i1 %= n; i2 %= n;
    if(i1 > i2){
        return prefSum[n] - prefSum[i1] + prefSum[i2];
    }
    return prefSum[i2] - prefSum[i1];

    // use prefix sum vector
}


int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
    // freopen("TASK_NAME.in", "r", stdin);
    // freopen("TASK_NAME.out", "w", stdout);
    // Use scanf printf

    cin >> n;
    
    vector<int> scores(n);
    prefSum.resize(n + 1);
    prefSum[0] = 0;
    int maxNumHacked = (n + 1) / 2;
    int splitLen = (n-1) / 2;
    int totSum = 0;

    for(int i = 0; i < n; i++){
        cin >> scores[i];
        totSum += scores[i];
        prefSum[i+1] = prefSum[i] + scores[i];
    }

    if(n == 2){
        cout << max(scores[0], scores[1]) << '\n';
        return 0;
    }

    int maxScore = INT32_MIN;

    for(int i = 0; i < n; i++){
        // cout << i + 1 << ' ' << i + 1 + splitLen << ' ' << getCumSum(i + 1, i + 1 + splitLen) << '\n';
        // cout << i + (n+1)/2 << ' ' << i + (n+1)/2 + splitLen << ' ' << getCumSum(i + (n+1)/2, i + (n+1)/2 + splitLen) << '\n';
        // cout << '\n';
        maxScore = max(maxScore, min(getCumSum(i + 1, i + 1 + splitLen), getCumSum(i + (n+1)/2, i + (n+1)/2 + splitLen)) + scores[i]);
    }
    // for(int el: prefSum){
    //     cout << el << ' ';
    // }
    
    cout << maxScore << '\n';








    // int windowScore = 0;
    // for(int i = 0; i < maxNumHacked; i++){
    //     windowScore += scores[i];
    // }

    // int minDiff = windowScore * 2 - totSum;
    // int bestScore = windowScore;

    // for(int i = 0; i < n; i++){
    //     // compare window starting at i
    //     // subtract element at i, add next element
    //     if(abs(windowScore * 2 - totSum) < minDiff && windowScore > totSum - windowScore){
    //         minDiff = windowScore * 2 - totSum;
    //         bestScore = windowScore;
    //     }

    //     // maxScore = min(minDiff, windowScore);

    //     windowScore -= scores[i];
    //     windowScore += scores[(i + maxNumHacked) % n];

    // }
    // cout << bestScore << '\n';
}

Compilation message (stderr)

hac.cpp: In function 'int main()':
hac.cpp:40:9: warning: unused variable 'maxNumHacked' [-Wunused-variable]
   40 |     int maxNumHacked = (n + 1) / 2;
      |         ^~~~~~~~~~~~

• Subtask 1: 0 / 20
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 40