Buy Low, Sell High

#include <iostream>
#include <vector>
#include <cmath>
#include <string>

using namespace std;

typedef long long LL;

int main(){
	int n; cin>>n;
	vector<int> nums;
	for (int i = 0; i < n; i++) {
		int qwe; cin>>qwe;
		nums.emplace_back(qwe);
	}
	vector<int> left(n);
	vector<int> right(n);
	
	int minv = 1e9;
	int maxv = -1;
	for (int i = 0; i < n; i++) {
		minv = min(nums[i], minv);
		maxv = max(nums[i], maxv);
		left[i] = maxv - minv;
	}

	minv = 1e9;
	maxv = -1;
	for (int i = n-1; i >= 0; i--) {
		minv = min(nums[i], minv);
		maxv = max(nums[i], maxv);
		right[i] = maxv - minv;
	}
	int ans = 0;
	for (int i = 0; i < n; i++) {
		ans = max(ans, left[i] + right[i]);
	}
	cout << ans;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: ACCEPTED