CODE 12: Best Time to Buy and Sell Stock

Say you have an array for which the ith element
is the price of a given stock on day i.

If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.

public int maxProfit(int[] prices) {
// Start typing your Java solution below
// DO NOT write main() function
if (null == prices || prices.length <= 1) {
return 0;
}
int currentMin = prices[0];
int max = 0;
for (int i = 0; i < prices.length; i++) {
if (prices[i] < currentMin) {
currentMin = prices[i];
}
int tmpMax = prices[i] - currentMin;
if (tmpMax > max) {
max = tmpMax;
}
}
return max;
}