exercism/zig/hamming/hamming.zig

pub const DnaError = error{
    EmptyDnaStrands,
    UnequalDnaStrands,
};

pub fn compute(first: []const u8, second: []const u8) DnaError!usize {
    if (first.len == 0 or second.len == 0) return DnaError.EmptyDnaStrands;
    if (first.len != second.len) return DnaError.UnequalDnaStrands;

    var count: usize = 0;
    for (first, second) |i, j| {
        if (i != j) count += 1;
    }
    return count;
}