My solution to a “Daily Coding Problem” that I received in my mail today.

Given a multiset of integers, return whether it can be partitioned into two subsets whose sums are the same.

For example, given the multiset `{15, 5, 20, 10, 35, 15, 10}`, it would return true, since we can split it up into `{15, 5, 10, 15, 10}` and `{20, 35},` which both add up to `55`.

Given the multiset `{15, 5, 20, 10, 35}`, it would return false, since we can’t split it up into two subsets that add up to the same sum.

Here’s my solution in Typescript,

``````sixty(arr: number[]): boolean {
if(arr == null) {
return false;
}
//step 1: check if the sum is odd?
const reducer = (v1: number, v2: number) => v1 + v2;
let total = arr.reduce(reducer);
if(total % 2 != 0) {
//if so then it's impossible to find 2 'equal' partitions
return false;
}
var returnVal = true;
let half = total / 2;
//get half and then find 2 subsets that total upto that no
return this.hasSubset(arr, arr.length, total / 2);
}
private hasSubset(arr: number[], idx: number, sum: number): boolean {
if(sum == 0) {
return true;
} else if(idx == 0 && sum != 0) {
return false;
}
if(arr[idx - 1] > sum) {
return this.hasSubset(arr, idx - 1, sum);
}
return this.hasSubset(arr, idx - 1, sum)
|| this.hasSubset(arr, idx -1 , sum - arr[idx -1] );
}``````

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