You are given an array of `intervals`, where `intervals[i] = [starti, endi]` and each `starti` is unique.

The right interval for an interval `i` is an interval `j` such that `startj >= endi` and `startj` is minimized. Note that `i` may equal `j`.

Return an array of right interval indices for each interval `i`. If no right interval exists for interval `i`, then put `-1` at index `i`.

Example 1:

    Input: intervals = [[1,2]]
    Output: [-1]
    Explanation: There is only one interval in the collection, so it outputs -1.

Example 2:

    Input: intervals = [[3,4],[2,3],[1,2]]
    Output: [-1,0,1]
    Explanation: There is no right interval for [3,4].
    The right interval for [2,3] is [3,4] since start0 = 3 is the smallest start that is >= end1 = 3.
    The right interval for [1,2] is [2,3] since start1 = 2 is the smallest start that is >= end2 = 2.

Example 3:

    Input: intervals = [[1,4],[2,3],[3,4]]
    Output: [-1,2,-1]
    Explanation: There is no right interval for [1,4] and [3,4].
    The right interval for [2,3] is [3,4] since start2 = 3 is the smallest start that is >= end1 = 3.

Constraints:

- `1 <= intervals.length <= 2 * 104`
- `intervals[i].length == 2`
- `-106 <= starti <= endi <= 106`
- The start point of each interval is unique.