fix haoel#196 - correct the level of difficulty

haoel · haoel · commit b5c2b7f7aa79 · 2020-01-16T10:16:34.000+08:00
diff --git a/README.md b/README.md
@@ -101,7 +101,7 @@ LeetCode
 |403|[Frog Jump](https://leetcode.com/problems/frog-jump/) | [C++](./algorithms/cpp/frogJump/FrogJump.cpp)|Hard|
 |402|[Remove K Digits](https://leetcode.com/problems/remove-k-digits/) | [C++](./algorithms/cpp/removeKDigits/RemoveKDigits.cpp)|Medium|
 |401|[Binary Watch](https://leetcode.com/problems/binary-watch/) | [C++](./algorithms/cpp/binaryWatch/BinaryWatch.cpp)|Easy|
-|400|[Nth Digit](https://leetcode.com/problems/nth-digit/) | [C++](./algorithms/cpp/nthDigit/NthDigit.cpp)|Easy|
+|400|[Nth Digit](https://leetcode.com/problems/nth-digit/) | [C++](./algorithms/cpp/nthDigit/NthDigit.cpp)|Medium|
 |399|[Evaluate Division](https://leetcode.com/problems/evaluate-division/) | [C++](./algorithms/cpp/evaluateDivision/EvaluateDivision.cpp)|Medium|
 |398|[Random Pick Index](https://leetcode.com/problems/random-pick-index/) | [C++](./algorithms/cpp/randomPickIndex/RandomPickIndex.cpp)|Medium|
 |397|[Integer Replacement](https://leetcode.com/problems/integer-replacement/) | [C++](./algorithms/cpp/integerReplacement/IntegerReplacement.cpp)|Medium|
