int maxProfit(std::vector<int>& prices) {

int maxPro{0}, mn{INT_MAX};

for(size_t i{0};i<prices.size();i++)

{

mn=std::min(mn,prices[i]);

maxPro=std::max(maxPro,prices[i]-mn);

}

return maxPro;

}

int maxProfit_v2(std::vector<int>& prices)

{

int currentMax {0}, max{0};

for(int i=0; i<prices.size()-1; ++i)

{

int diff = prices[i+1] - prices[i];

if(diff == 0) continue;

// if previous profit is less than the current one (negative profit = loss)

// then it should be discarded

// that is why maximum of (diff+currentMax) and diff

// is checked here

// For instance 4 6 1 2 3 5 in this array after 6 the

// algorithm should be restarted because max diff is 5 -1 = 4.

// so max(-5+3 , 2-1) = 1, so calculation will start from 1.

currentMax = std::max(diff+currentMax, diff);

max = std::max(currentMax, max);

}

return max;

}

{

std::vector<int> prices {7,1,5,3,6,4};

std::cout<<Solution().maxProfit(prices);

std::cout<<std::endl; // 5

std::vector<int> prices2 {1,2};

std::cout<<Solution().maxProfit(prices2); // 1

std::cout<<std::endl;

std::cout<<Solution().maxProfit_v2(prices); // 5

}