public int maxProfit(int[] prices) {

          if(prices.length==0)return 0;

          int maxProfit=0;

          int min=prices[0];

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

          {

              maxProfit=prices[i]-min>maxProfit?prices[i]-min:maxProfit;

              min=prices[i]<min?prices[i]:min;

          }

          return maxProfit;

      }