Za to sto treba da uradis netrebaju ti nikakve biblioteke, vec vrlo malo programerskog znanja, bez uvrede. Pogledaj malo FOR petlje i IF uslove uz malo mozganja logicki ces vec sam doci do resenja.

Sto se tice drugog pitanja, dokumentaciju za najnoviju verziju SDK 1.4.2 mozes naci na:

http://java.sun.com/j2se/1.4.2/download.html

skini - J2SE v 1.4.2 Documentation

Ma da - bolje je da covek nadje JAVA .jar od par mega koji se bavi kombinatorikom.. :>>> Sto da se muci da napise tako nesto u 10-20 linija JAVA koda, kad to moze besplatno da nadje zapakovano i spremno za upotrebu?

A ako te ne interesuju moguce vrijednosti vec samo broj kombinacija pronadji negdje formule za kombinatoriku, tj permutacije, kombinacije sa i bez ponavljanja..

Posle mnogo mukotrpnog rada, uspeo sam. Ne samo da resim onaj problem gore, to je bilo tesko, ali jako prosto kada se nadje resjenje, vec i ceo zadatak. I sto je najbolje, nisam nista koristio sem iostream... Ovo je zadatak:

Write a program that takes as input a numeric string (i.e. a string that consists only of the numeric digits 0 through 9) and uses recursion to answer the following problem: is there any way to add mathematical operators into the string such that the result is a valid mathematical equation?

The following strings have valid solutions:

"2317" (solution: "2*3+1=7")
"05555" (solution: "0*5*5+5=5")
"2284" (solution: "2*2=8-4")
"11112" (solution "1+11=12")
"123123" (solution: "123=123")
The following operators are valid (and have standard meaning): "+", "*", "/", "-", "%", "=". Integer division should be used for the "/" operator. Negative numbers are not allowed (so given the string "143", "-1+4=3" is not a valid solution). The "=" can only appear once in a valid solution (note that both "1*1=1" and "1=1*1" are valid solutions to the string "111"). Lastly, you may assume "left-to-right" arithmetic operations (i.e. 1+4*2-7 equals 3, since proceeding from left to right we first perform the addition, then the multiplication, then the subtraction).

Your program should take the user's input, print out whether or not the string has any valid solutions, and print out (any) valid solution if one exists.