📦 Collections Without Iterators

Compute prefix sums: each element of the result is the sum of all input elements up to that point. The caller owns the returned slice and must free it with allocator.free(result).

`items`	result
`[1, 2, 3, 4]`	`[1, 3, 6, 10]`
`[5]`	`[5]`
`[]`	`[]`

The result always contains exactly items.len elements, so allocate that slice directly with allocator.alloc(i32, items.len).

Iterate over the input and output together with for (items, result) |item, *output|. Update the running sum, then store it through output.*.

Zig

/// Return prefix sums of the input slice
fn prefixSums(
    allocator: std.mem.Allocator,
    items: []const i32,
) std.mem.Allocator.Error![]i32 {
    const result = try allocator.alloc(i32, items.len);

    var running: i32 = 0;
    for (items, result) |item, *output| {
        running += item;
        output.* = running;
    }

    return result;
}

Prefix Sums

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