CSES - HIIT Open 2018 - Results
Submission details
Task:Buy Low, Sell High
Sender:Lucinda
Submission time:2018-05-26 12:37:33
Language:C++
Status:READY
Result:ACCEPTED
Test results
testverdicttime
#1ACCEPTED0.09 sdetails
#2ACCEPTED0.23 sdetails
#3ACCEPTED0.20 sdetails
#4ACCEPTED0.23 sdetails
#5ACCEPTED0.22 sdetails
#6ACCEPTED0.01 sdetails
#7ACCEPTED0.01 sdetails
#8ACCEPTED0.01 sdetails
#9ACCEPTED0.08 sdetails

Code

#include <iostream>
#include <string>
#include <stdio.h>
#include <math.h>
#include <vector>

using namespace std;

int main() {
    int n;
    cin >> n;
    int *a = new int[n];
    
    for (int i = 0; i < n; i++)
        cin >> a[i];

    int *b_pref = new int[n];
    int *b_suf = new int[n];
    b_pref[0] = 0; // first day buy and sell
    b_suf[n - 1] = 0; // last day buy and sell

    int lowest = a[0];
    
    for (int i = 1; i < n; i++) { // points at end of period
        int end = a[i];
        int best_so_far = b_pref[i - 1];
        
        if (end - lowest > best_so_far) b_pref[i] = end - lowest;
        else b_pref[i] = best_so_far;

        if (end < lowest) lowest = end;
    }
    
    /* cout << endl;
    for (int i = 0; i < n; i++)
        cout << b_pref[i] << " ";
    */
    int highest = a[n - 1];
    for (int i = n - 2; i >= 0; i--) { // points at the start of period
        int start = a[i];
        int best_so_far = b_suf[i + 1];
        
        if (highest - start > best_so_far) b_suf[i] = highest - start;
        else b_suf[i] = best_so_far;

        if (start > highest) highest = start;
    }

    /* cout << endl;
    for (int i = 0; i < n; i++)
        cout << b_suf[i] << " ";
    */
    int best = 0;
    for (int i = 0; i < n; i++) {
        if (b_pref[i] + b_suf[i] > best)
            best = b_pref[i] + b_suf[i];
    }
    cout << best << endl;
    
    delete[] a;
    delete[] b_pref;
    delete[] b_suf;
}

Test details

Test 1

Verdict: ACCEPTED

input
500000
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...

correct output
0

user output
0

Test 2

Verdict: ACCEPTED

input
500000
1 2 3 4 5 6 7 8 9 10 11 12 13 ...

correct output
499999

user output
499999

Test 3

Verdict: ACCEPTED

input
500000
500000 499999 499998 499997 49...

correct output
0

user output
0

Test 4

Verdict: ACCEPTED

input
500000
617752857 533265574 365848360 ...

correct output
1999980408

user output
1999980408

Test 5

Verdict: ACCEPTED

input
500000
209620375 316066031 756114325 ...

correct output
1999992655

user output
1999992655

Test 6

Verdict: ACCEPTED

input
1
1

correct output
0

user output
0

Test 7

Verdict: ACCEPTED

input
2
1 1

correct output
0

user output
0

Test 8

Verdict: ACCEPTED

input
2
2 1

correct output
0

user output
0

Test 9

Verdict: ACCEPTED

input
500000
1 1000000000 2 2 2 2 2 2 2 2 2...

correct output
1999999998

user output
1999999998