I don't get why "111" is considered as an 'E', can enyone enlighten me please.

Yes solved, thank you!

When running the example I got a reference error, the same error is fired when running the test suit, the log generated is below:

../home/codewarrior/spec.ts(1,1): error TS1084: Invalid 'reference' directive syntax.
../home/codewarrior/spec.ts(2,1): error TS1084: Invalid 'reference' directive syntax.

I fixed the example by adding those lines to the top

/// <reference path="/runner/typings/main/ambient/mocha/index.d.ts" />
/// <reference path="/runner/typings/main/ambient/chai/index.d.ts" />

instead of

/// <reference path="/runner/typings/main/ambient/mocha/index.d.ts" ></reference>
/// <reference path="/runner/typings/main/ambient/chai/index.d.ts" ></reference>

Can you please fix the test suite too?

Nope it's not called cheating, it's called preprocessing, it's definitely allowed in competitive programming.