java - Shifting in arrayList -
the method public static <t> arraylist<t> rotate(arraylist<t> al, int shift) accepts arraylist of string (at least in example) , shift indicated how arraylist should shift. if have, let's araylist of
[ a, b, c, d, e, f, g] and shift 2, method returns
[ f, a, b, c, d, e] or example,
[ a, b, c, d, e, f, g] and shift 4, method returns
[ d, e, f, g, a, b, c] i did method wrong , have no clue how approach problem. smb me ?
import java.util.arraylist; public class rotation{ // demonstrate rotat(a,shift) method public static void main(string arg[]){ arraylist<character> charsl; charsl = new arraylist<character>(); char [] chars = { 'a', 'b', 'c', 'd', 'e', 'f'}; for(char c : chars){ charsl.add(c); } // charsl = [ a, b, c, d, e, f] arraylist<character> result1; result1 = rotate(charsl, 2); // result1== [ e, f, a, b, c, d] system.out.println(result1); result1 = rotate(charsl, 7); // result1== [ f, a, b, c, d, e] system.out.println(result1); // works srtings arraylist<string> stringl; stringl = new arraylist<string>(); string [] strs = { "a", "b", "c", "d", "e", "f", "g" }; for(string s : strs){ stringl.add(s); } // stringl = [ a, b, c, d, e, f, g] arraylist<string> result2; result2 = rotate(stringl, 7); // result2== [ a, b, c, d, e, f, g] system.out.println(result2); result2 = rotate(stringl, 4); // result2== [ d, e, f, g, a, b, c] system.out.println(result2); } public static <t> arraylist<t> rotate(arraylist<t> al, int shift){ // definition here arraylist <t> newvalues = new arraylist<>(); arraylist <t> temp = new arraylist<>(); for(int = 0; < al.size(); i++) { newvalues.remove(al.get(shift)); newvalues.add(al.get(i)); //newvalues.add(shift, al.get(i)); } return newvalues; } }
try this:
public static <t> arraylist<t> rotate(arraylist<t> al, int shift) { if (al.size() == 0) return al; t element = null; for(int = 0; < shift; i++) { // remove last element, add front of arraylist element = al.remove( al.size() - 1 ); al.add(0, element); } return al; }