title: Finding duplicate values in dictionary and print Key of the duplicate element
body: <p>What can be the <strong>fastest</strong> way to to check the duplicate values in the dictionary and print its key?</p>
  
  <p>Dictionary <code>MyDict</code> which is having following values,</p>
  
  <p>Key  <strong>Value</strong></p>
  
  <p>22     <strong>100</strong></p>
  
  <p>24     <strong>200</strong></p>
  
  <p>25     <strong>100</strong></p>
  
  <p>26     <strong>300</strong></p>
  
  <p>29     <strong>200</strong></p>
  
  <p>39     <strong>400</strong></p>
  
  <p>41     <strong>500</strong></p>
  
  <p>Example: key 22 and 25 have same values and  i need to print that 22 and 25 have duplicate values.</p>