Buy Low, Sell High

#include <iostream>

using namespace std;

int main() {
    int le, e;
    cin >> le;

    int l[le] = {0};
    int a[le] = {0};

    for (int i = 0; i < le; i++) {
        cin >> e;
        l[i] = e;
    }


    a[0] = -l[0];
    for (int i = 1; i < le; i++)
     a[i] = max(a[i-1],-l[i]);

    a[0] = 0;
    for (int i = 1; i < le; i++)
     a[i] = max(a[i-1], a[i] + l[i]);

    a[0] = -l[0];
    for (int i = 1; i < le; i++)
     a[i] = max(a[i-1], a[i] - l[i]);

    a[0] = 0;
    for (int i = 1; i < le; i++)
     a[i] = max(a[i-1], a[i] + l[i]);

    cout << a[le - 1] << endl;


    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED