I think the problem description is not clear...

The range elimation is based on the vector after the element elimination.

For example, in the sample input:

6

1 4 6 2 8 9

2

2 4

The first elimination is to erase the 2nd element in the vector, which is 4. Then, based on the new vector {1 6 2 8 9}, we want to remove the range of 2~4, which means the 2nd and 3rd elements should be removed. Then 6 and 2 in the new vector are removed and we finally got {1 8 9} as the final result...

Hope the above help those who did not get what the problem asks us to code...

Not using zero-indexed array indices in this problem is needlessly confusing.

Vector does not have the methods

erase(int)
erase(int, int)

as the tutorial states. The correct methods signatures are

iterator erase (iterator position);
iterator erase (iterator first, iterator last);

the problem description is so disgusting. couldn't make sny sense ..