Merge pull request #139 from jayalloyd/feature/java-stock-profit

feat(java): Add O(n) solution for Buy and Sell Stock problem to Arrays

Author: admirerr

Java/arrays/BuyAndSellStockCode.java

@@ -0,0 +1,30 @@
+public class BuyAndSellStockCode {
+    public static int buyAndSellStock(int []prices){
+
+        int buyPrice=Integer.MAX_VALUE;
+        
+        int maxProfit=0;
+        //track lowest buying price
+        for(int i=0;i<prices.length;i++){
+            if(buyPrice<prices[i]){//profit
+                int profit=prices[i]-buyPrice;
+                maxProfit=Math.max(maxProfit, profit);//todays profit
+            
+
+            }else {
+
+                buyPrice=prices[i];
+                
+            }
+
+        }
+        return maxProfit;
+    }
+    
+    
+    public static void main(String[] args) {
+        int [] prices={7,1,5,3,6,4};
+       System.out.println(buyAndSellStock(prices));
+    }
+}
+/* time complexity 0(n) is proportional to n*/