1282. Group the People Given the Group Size They Belong To

There are `n` people that are split into some unknown number of groups. Each person is labeled with a unique ID from `0` to `n - 1`.

You are given an integer array `groupSizes`, where `groupSizes[i]` is the size of the group that person `i` is in. For example, if `groupSizes[1] = 3`, then person `1` must be in a group of size `3`.

Return a list of groups such that each person `i` is in a group of size `groupSizes[i]`.

Each person should appear in exactly one group, and every person must be in a group. If there are multiple answers, return any of them. It is guaranteed that there will be at least one valid solution for the given input.

Example 1:

```Input: groupSizes = [3,3,3,3,3,1,3]
Output: [[5],[0,1,2],[3,4,6]]
Explanation:
The first group is [5]. The size is 1, and groupSizes[5] = 1.
The second group is [0,1,2]. The size is 3, and groupSizes[0] = groupSizes[1] = groupSizes[2] = 3.
The third group is [3,4,6]. The size is 3, and groupSizes[3] = groupSizes[4] = groupSizes[6] = 3.
Other possible solutions are [[2,1,6],[5],[0,4,3]] and [[5],[0,6,2],[4,3,1]].
```

Example 2:

```Input: groupSizes = [2,1,3,3,3,2]
Output: [[1],[0,5],[2,3,4]]
```

Constraints:

• `groupSizes.length == n`
• `1 <= n <= 500`
• `1 <= groupSizes[i] <= n`

1282. Group the People Given the Group Size They Belong To
``````struct Solution;

type Person = (i32, usize);

impl Solution {
fn group_the_people(group_sizes: Vec<i32>) -> Vec<Vec<i32>> {
let mut people: Vec<Person> = vec![];
let mut res: Vec<Vec<i32>> = vec![];
for (id, &group_size) in group_sizes.iter().enumerate() {
people.push((group_size, id))
}
people.sort_unstable();
let mut group: Vec<i32> = vec![];
for p in people {
group.push(p.1 as i32);
if group.len() == p.0 as usize {
res.push(group);
group = vec![];
}
}
res
}
}

#[test]
fn test() {
let group_sizes = vec![3, 3, 3, 3, 3, 1, 3];
let res = vec_vec_i32![[5], [0, 1, 2], [3, 4, 6]];
assert_eq!(Solution::group_the_people(group_sizes), res);
let group_sizes = vec![2, 1, 3, 3, 3, 2];
let res = vec_vec_i32![[1], [0, 5], [2, 3, 4]];
assert_eq!(Solution::group_the_people(group_sizes), res);
}
``````