Which Ones Slide

Each statement below describes a query over an array of integers. More than one admits a correct linear two-pointer or sliding-window solution. Select every one that does.

Longest contiguous subarray containing at most 3 distinct values

The contiguous subarray with the largest sum, values may be negative

Longest contiguous subarray with sum at most $T$ , given that every value is positive

Given a sorted array, decide whether two elements sum to $X$

Longest contiguous subarray with sum at most $T$ , values may be negative