1282 Group the People Given the Group Size They Belong To
Problem Statement
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.
Input: groupSizes = [3,3,3,3,3,1,3]
Output: [[5],[0,1,2],[3,4,6]]
Approach
We are using a Hash Table to store group sizes as a key with a bucket (array) of each persons index as a value. Once one of these buckets has the length that matches the person we push that into the results array and clear out the bucket
Solution
var groupThePeople = function(groupSizes) {
let result = [],
hash = {}
for (const [index, person] of groupSizes.entries()){
hash[person] ? hash[person].push(index) : hash[person] = [index]
if (hash[person].length === person) {
result.push(hash[person]);
hash[person] = [];
}
}
return result
};