The minimum fibonacci challenge!

Question

Challenge

In this task you would be given an integer N (less than 10⁶), find the minimum way in which you could sum to N using only Fibonacci numbers - this partition is called Zeckendorf representation.

You could use any Fibonacci number more than once and if there is more than one representation output any.

For example if the input is 67 then one possible output could be using the Fibonacci numbers 1,3,8,55 which is also the minimum number of Fibonacci numbers that could be used to get the sum 67.

The input N is given on a single line, the inputs are terminated by EOF.

Examples

Given in the format input: output

0: 0
47: 34+13
3788: 2584+987+144+55+13+5
1646: 1597+34+13+2
25347: 17711+6765+610+233+21+5+2
677: 610+55+8+3+1
343: 233+89+21
3434: 2584+610+233+5+2

Constraints

• The number of inputs would not exceed 10⁶ values.
• Your program should not run more than 5 seconds for all inputs.
• You can use any language of your choice.
• Shortest solution wins!

Answer 1

Motorola 68000 assembly - 34 bytes

(GNU assembler syntax)

| short min_fib_partition(long N asm("%d2"), long *out asm("%a0"))
min_fib_partition:
    | Generate Fibonacci numbers on the stack (-1, 1, 0, 1, 1, 2, 3, ..., 1134903170).
    moveq #-1, %d0          | A = -1
    moveq #1, %d1           | B = 1
generate_loop:
    move.l %d0, -(%sp)      | Push A to the stack.
    exg.l %d0, %d1          | A' = B
    add.l %d0, %d1          | B' = A + B
    bvc.s generate_loop     | Stop when signed long overflows.

    | Go back up the stack, partitioning N using the greedy algorithm.
    moveq #0, %d0           | Initialize return value (number of terms).
subtract_loop:
    move.l (%sp)+, %d1      | Pop a Fibonacci number F off the stack.
    cmp.l %d1, %d2          | If N < F, continue to smaller Fibonacci number.
    blt.s subtract_loop
    addq.w #1, %d0          | Increment the term count.
    move.l %d1, (%a0)+      | Append F to the output array.
    sub.l %d1, %d2          | N -= F
    bne.s subtract_loop     | Continue if N has not yet reached zero.

    | Clear the stack by searching for that -1.
clear_stack_loop:
    tst.l (%sp)+
    bge clear_stack_loop

done:
    rts

36 → 34: Made Fibonacci generator stop on overflow rather than by counting, and fixed the 0 case so it outputs [0] rather than []. However, passing a negative N crashes now.

The comment at the top is the C prototype of this function, using a language extension to identify what parameters go where (by default, they go on the stack).

My TI-89, with its 10MHz processor, takes 5 minutes to run this function on 1 ­– 1,000,000.

Although the machine code is (currently) fewer bytes than the GolfScript solution, it would probably be unfair to accept this as the shortest solution because:

• Machine code is normally not counted as "source code". Unlike source code, machine code usually has high symbol complexity and, more importantly, is unprintable. See "Should executable binaries be considered a reasonable solution for code-golf?".
• This solution only takes a single number as input, rather than multiple inputs.
• This solution is a function, not a program.

If you have a TI-89/92/V200, you can download the full project here (outdated):

https://rapidshare.com/files/154945328/minfib.zip

Good luck coaxing RapidShare to give you the actual file. Does anyone know of a good host for files this big? 8940 is an awful lot of bytes.

Answer 2

Javascript (142)

Only handles single input at a time. Because multi-line input is useless for JavaScript.

k=n=prompt(f=[a=b=1])|0;while((b=a+(a=b))<n)f.push(b);for(i=f.length,g=[];i--;)if(f[i]<=k)g.push(f[i]),k-=f[i];alert(n+': '+(n?g.join('+'):0))

http://jsfiddle.net/EqMXQ/

Answer 3

C, 244 characters

#define P printf
int f[30];int main(){f[28]=f[29]=1;int i=28;for(;i>0;--i)f[i-1]=f[i+1]+f[i];int x;while(scanf("%i",&x)!=-1){P(x?"%i: ":"0: 0\n",x);if(x>0){int i=0,a=0;while(x>0){while(f[i]>x)++i;if(a++)P("+");P("%i",f[i]);x-=f[i];}P("\n");}}}

With whitespace:

#define P printf
int f[30];
int main(){
    f[28] = f[29] = 1;
    int i = 28;
    for(; i > 0; --i) f[i-1] = f[i+1] + f[i];
    int x;
    while(scanf("%i",&x) != -1) {
        P(x ? "%i: " : "0: 0\n",x);
        if(x > 0) {
            int i = 0, a = 0;
            while(x > 0) {
                while(f[i] > x) ++i;
                if(a++) P("+");
                P("%i",f[i]);
                x -= f[i];
            }
            P("\n");
        }
    }
}

This program will read numbers out of standard input and write to standard output.

Answer 4

Golfscript, 43 chars

~]{:|': '[{0 1{|>!}{.@+}/;|1$-:|}do]'+'*n}%

I think this can probably be reduced by 3 to 5 chars with more effort. E.g. the unfold to then throw away the array feels wasteful.

Answer 5

F# - 282 252 241 characters

let mutable d=int(stdin.ReadLine())
let q=d
let rec f x=if x<2 then 1 else f(x-2)+f(x-1)
let s x=
 d<-d-x
 x
printf"%d: %s"q (Core.string.Join("+",[for i in List.filter(fun x->x<d)[for i in 28..-1..0->f i]do if d-i>=0 then yield s i]))

Answer 6

Python - 183 Chars

Majority of the code is handling multiple inputs :(

f=lambda a,b,n:b>n and a or f(b,a+b,n)
g=lambda n:n>0and"%d+%s"%(f(0,1,n),g(n-f(0,1,n)))or""
try:
 while 1:
  n=input()
  print "%d: %s"%(n,n<1and"0"or g(n).strip("+"))
except:0

Answer 7

Mathematica 88

n = RandomInteger[10000, 10];

Print[k=#,For[i=99;l={},k>0,If[#<=k,k-=#;l~AppendTo~#]&@Fibonacci@i--];":"l~Row~"+"]&/@n

Example of output

3999: 2584+987+377+34+13+3+1
9226: 6765+1597+610+233+21
7225: 6765+377+55+21+5+2
9641: 6765+2584+233+55+3+1
6306: 4181+1597+377+144+5+2
4507: 4181+233+89+3+1
8848: 6765+1597+377+89+13+5+2
6263: 4181+1597+377+89+13+5+1
2034: 1597+377+55+5
6937: 6765+144+21+5+2

Answer 8

EXCEL : 89 chars in unique code:

Answer 9

Scala - 353 chars (100 chars for handling multiple inputs)

def h(m:Int){lazy val f={def g(a:Int,b:Int):Stream[Int]=a #:: g(b,a+b);g(0,1);};if(m==0)println(m+": "+m)else{var s=0;var t= f.takeWhile(_ <= m);var w="";while(s!= m){s+=t.last;w+=t.last+"+";t=t.takeWhile(_<=m-s);};println(m+": "+w.take(w.length-1))}}
Iterator.continually(Console.readLine).takeWhile(_ != "").foreach(line => h(Integer.parseInt(line)))

Answer 10

Python 3 (170 chars)

while 1:
 s=input()
 if not s:break
 s=n=int(s);f=[1];t=[]
 while f[-1]<n:f+=[sum(f[-2:])]
 for i in f[::-1]:
  if s>=i:s-=i;t+=[i]
 print(n,'=','+'.join(map(str,t))or 0)

Multiline input, stop on empty line

Answer 11

C, 151 characters

main() {int i=1,n,f[30]={1,1};for(;i++<30;)f[i]=f[i-1]+f[i-2];while(scanf("%d",&n))for(i=30;;--i)if(f[i]<=n){printf("%d\n",f[i]);if(!(n-=f[i]))break;}}

readable version:

main() {
    int i=1,n,f[30]={1,1};
    for(;i++<30;)f[i]=f[i-1]+f[i-2];
    while(scanf("%d",&n))
        for(i=30;;--i)
            if(f[i]<=n) {
                printf("%d\n",f[i]);
                if (!(n-=f[i])) break;
            }
}

Answer 12

R, 170

x=scan();Filter(function(i)cat(unlist(Map(function(d)if(i>=d&&i){i<<-i-d;d},rev(lapply(Reduce(function(f,x)c(f[2],sum(f)),1:94,c(0,1),F,T),head,n=1)))),sep='+',fill=T),x)

Handles multiple inputs and cat's the result to STDOUT

> x=scan();Filter(function(i)cat(unlist(Map(function(d)if(i>=d&&i){i<<-i-d;d},rev(lapply(Reduce(function(f,x)c(f[2],sum(f)),1:94,c(0,1),F,T),head,n=1)))),sep='+',fill=T),x)
1: 100
2: 200
3: 300
4: 
Read 3 items
89+8+3
144+55+1
233+55+8+3+1
numeric(0)
>

Answer 13

R (460 chars)

Another version using R.
Reading from file "input", output to the file "output"

d=as.list(as.integer(scan("input","",sep="\n")));n=36;f=rep(1,n);for(i in 3:n){f[i]=f[i-2]+f[i-1]};d2=lapply(d,function(x){a=vector("integer");i=1;while(x>0){id=which(f>=x)[1];if(x==f[id]){x=x-f[id];a[i]=f[id]}else{x=x-f[id-1];a[i]=f[id-1]}i=i+1}a});d=mapply(c,d,d2,SIMPLIFY=0);for(i in 1:length(d)){t=d[[i]];l=length(t);if(l==1){d[[i]]=paste(t[1],t[1],sep=": ")}else{d[[i]]=paste(t[1],": ",paste(t[2:l],collapse="+"),sep="")}}lapply(d,write,"output",append=1)

"input" example

0
47
3788
1646
25347
677
343
3434

"output" example

0: 0
47: 34+13
3788: 2584+987+144+55+13+5
1646: 1597+34+13+2
25347: 17711+6765+610+233+21+5+2
677: 610+55+8+3+1
343: 233+89+21
3434: 2584+610+233+5+2

More readable version:

dt <- as.list(as.integer(scan(file = "input", what = "", sep = "\n")))
n <- 36
fib <- rep(1, n)
for(i in 3:n){fib[i] <- fib[i-2] + fib[i-1]}
dt2 <- lapply(dt, function(x){answ <- vector(mode = "integer")
                               i <- 1
                               while(x > 0){
                                   idx <- which(fib>=x)[1]
                                   if(x == fib[idx]){
                                       x <- x - fib[idx]
                                       answ[i] <- fib[idx]
                                   } 
                                   else {
                                       x <- x - fib[idx-1]
                                       answ[i] <- fib[idx-1]
                                   }
                                   i <- i + 1
                               }
                               answ})
dt <- mapply(FUN = c, dt, dt2, SIMPLIFY = FALSE)
for(i in 1:length(dt)){
    t1 <- dt[[i]]
    t1.len <- length(t1)
    if(t1.len == 1){
        dt[[i]] <- paste(t1[1], t1[1], sep=": ")
    } else {
        dt[[i]] <- paste(t1[1], ": ", paste(t1[2:t1.len], collapse = "+"), sep="")
    }
}
lapply(dt, write, "output", append=TRUE)

Answer 14

D (196 chars)

Run with rdmd --eval=…. This conveniently hides the boilerplate of import x, y, z; and void main() {…}:

int f(int i){return i-->1?f(i--)+f(i):i+2;}int n;foreach(x;std.stdio.stdin.byLine.map!(to!int))writeln(x,": ",x?n=x,reduce!((r,i)=>f(i)<=n?n-=f(i),r~="+"~f(i).text:r)("",29.iota.retro)[1..$]:"0")

Answer 15

Using Java

package org.mindcraft;

import java.util.Scanner;

public class Fibbo {
    public static void main(String[] args) {
    String number = null;
    int tmp, sum;
    int i = 1, j = 1;
    Scanner in = new Scanner(System.in);
    number = in.nextLine();
    String[] arr = number.split(" ");
    for (int it = 0; it < arr.length; it++) {
        tmp = Integer.parseInt(arr[it]);
        String value = tmp+" : ";
        while (tmp > 0) {
            i = 1;
            j = 1;
            for (int k = 0; k < 10000; k++) {
                sum = i + j;
                if (sum > tmp) {
                    //if (value == null) {
                    char ch=value.charAt(value.length()-2);
                    if(ch==':')
                    {
                        value = value+" "+ j + "";
                    } else {
                        value = value + " + " + j;
                    }

                    tmp = tmp - j;
                    break;
                }
                i = j;
                j = sum;
            }
        }
        System.out.println(value);
    }
}
}