121. Buy and sell stocks best time to buy and Sell stock

Say you has an array for which the i-th element is the price of a given-stock on day I.

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

Example 1:

Input: [7, 1, 5, 3, 6, 4]output:5max. difference = 6-1 = 5 (Not 7-1 = 6, as selling-price needs-be-larger than buying price)

Example 2:

Input: [7, 6, 4, 3, 1]output:0in this case, no transaction was done, i.e. Max Profit = 0.

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Thinking: Dynamic planning

  
 

   
  

  
public class Solution {
   
  

  
 public int MaxProfit(int[] prices) {
   
  

  
 if (prices.Length == 0)
   
  

  
 {
   
  

  
 return 0;
   
  

  
 }
   
  

  
 int low = prices[0];
   
  

  
 int max = 0;
   
  

  
 int length = prices.Length;
   
  

  
 for (int i = 0; i < length; i++)
   
  

  
 {
   
  

  
 if (prices[i] < low)
   
  

  
 {
   
  

  
 low = prices[i];
   
  

  
 }
   
  

  
 else if (prices[i] - low > max)
   
  

  
 {
   
  

  
 max = prices[i] - low;
   
  

  
 }
   
  

  
 }
   
  

  
 return max;
   
  

  
 }
   
  

  
}
  
 

From for notes (Wiz)

121. Buy and sell stocks best time to buy and Sell stock