what will be the space complexity of this class? and why?
what will be the space complexity used by the function moveZeroes
class Solution {
public:
void moveZeroes(vector<int>& nums) {
vector<int>nums2(nums);
int j=0;
int numOfZeros=0;
for(int i=0;i<nums2.size();i++){
if(nums2[i]!=0){
nums[j]=nums2[i];
j++;
}
else{
numOfZeros++;
}
}
for (int k =numOfZeros; k >0 ; k--)
{
nums[j]=0;
j++;
}
}
};
Related
How we can decrees time complexity of finding subarray of a given array in O(n) from O(n^3)
void subArray(int arr[],int n)
{
int i=0,j,k;
while(i<n)
{
j=i;
while(j<n)
{
k=i;
while(k<=j)
{
cout<<arr[k]<<" ";
k++;
}
cout<<endl;
j++;
}
i++;
}
}
Below is a Sudoku initializer, I am attempting to create a function that based on User input, erases a random element from the the board. The random element can be removed from any part of the board.
class cell{
bool m_occu; //occupied is shown '.'
int m_num;
public:
cell() : m_occu(false), m_num(0) {}
void setMark(const int num){m_num = num; m_occu = true;}
bool isMarked() const { return m_occu; }
int getNum(){ return m_num;}
friend ostream& operator << (ostream& o, const cell& c){
if (!c.m_occu) return o << setw(2) << '-';
return o << setw(2) << c.m_num;
}
};
class board {
vector<vector <cell> >m_map;
bool col_row;
public:
board() {
vector<cell> a_row(9);
col_row = false;
for (int i = 0; i < 9; ++i)
{
for(int j = 0; j < 9; j++)
{
a_row[j].setMark(j+1);
}
random_shuffle(a_row.begin(), a_row.end());
m_map.push_back(a_row);
}
}
void erase(){
}
Here is the code for erase function:
void erase(std::vector your_vector){
your_vector.erase(your_vector.begin() + random(1,your_vector.size()));
}
and this the code for random number generation:
int random(int min, int max) //range(min, max)
{
bool first = true;
if ( first )
{
srand(time(NULL)); //seeding only for the first time
first = false;
}
return min + rand() % (max - min);
}
I'm trying to create a basic function that calls on a method that creates the 2D ArrayList that will be used further in the main program to do things like calculate the row and column sums as well as print out the triangle.
However, after it runs the ArrayList returns null. What's going on?
Thanks,
public class Trib
{
private ArrayList<ArrayList<Integer>> triangle;
private int Asize;
public Trib (int size)
{
// convert the argument to type 'int' to be used in the program
Asize = size;
// create an ArrayList of ArrayLists, it will have 'size' number ArrayLists contained within
ArrayList<ArrayList<Integer>> triangle = new ArrayList<ArrayList<Integer>>(size);
// create the inner ArrayLists
for (int i = 0; i < size; i++)
{
// add to index 'i' of our ArrayList a new ArrayList of size (i+1)
triangle.add(new ArrayList<Integer>(i+1));
for (int j = 0; j <= i; j++)
{
if (j==0 || j == i)
{
triangle.get(i).add(1);
}
else
triangle.get(i).add(triangle.get(i-1).get(j-1)+triangle.get(i-1).get(j));
System.out.print(triangle.get(i).get(j) + " ");
}
System.out.println();
}
triangle.clone();
}
public void printTriangle()
{
System.out.print(triangle.get(1).get(1));
/*for (int i = 0; i < Asize; i++)
{
for (int j = 0; j <= i; j++)
{
System.out.print(triangle.get(1).get(1) + " ");
}
System.out.println();
}*/
}
/*public Trib()
{
this(5);
}*/
/*public int Psize()
{
return triangle.size();
}
public ArrayList<Integer> sumRows()
{
ArrayList<Integer> row_sum = new ArrayList<Integer>(Asize);
for (int i = 0; i < Asize; i++)
{
for (int j = 0; j < i; j++)
{
row_sum.add(triangle.get(i).get(j));
}
}
return row_sum;
}
public ArrayList<Integer> sumCols()
{
ArrayList<Integer> col_sum = new ArrayList<Integer>(Asize);
for (int i = 0; i < Asize; i++)
{
for (int j = 0; j < i; j++)
{
col_sum.add(triangle.get(i).get(i));
}
}
return col_sum;
}*/
public static void main(String[] args)
{
if(args.length < 1)
{
System.err.println("Sorry, this program needs an integer argument.");
System.exit(1);
}
Trib pt = new Trib(Integer.parseInt(args[0]));
pt.printTriangle();
//ArrayList<Object> sum_rows = new ArrayList<Object>(pt.Psize());
// sum_rows.add;
System.out.println("\nHere are the sum of rows:");
//for (int i = 0; i < pt.Psize(); i++)
//System.out.println(sum_rows.get(i));
//ArrayList<Integer> sum_cols = new ArrayList<Integer>(pt.Psize());
System.out.println("\nHere are the sum of columns:");
//for (int i = 0; i < pt.Psize(); i++)
//System.out.printf("%-5d", sum_cols.get(i));
}
}
Watch out what's what you are doing: Notice that you have TWO variables named "triangle": The first one is an instance variable and the second is a local variable, which is the only one you have initialized.
My suggestion to avoid this common mistake is to pre-pend "this." to any use of what you intend must be an instance variable. And, if in doubt, if you use a development environment as Eclipse, press CTRL and click on your variable to navigate to the point where it is declared.
This is the code for solving sudoku (9x9):
#include <iostream>
#define dim 9
#define br_polja dim*dim
using namespace std;
bool Fsearch (int tab[dim][dim],int *x,int *y, int cand[dim], int *num_cand, int &free) {
int min=9;
*x=-1;
*y=-1;
free=0;
for (int i=0;i<dim;i++) {
for (int j=0;j<dim;j++) {
if (tab[i][j]!=0) continue;
free+=1;
*num_cand=0;
int cand_f[dim];
for (int w=0;w<dim;w++)
cand_f[w]=1;
int p,q;
p=i+3-(i%3);
q=j+3-(j%3);
for (int w=p-3;w<p;w++)
for (int r=q-3;r<q;r++)
if (tab[w][r]!=0){
cand_f[tab[w][r]-1]=0;
}
for (int w=0;w<dim;w++) {
if (tab[w][j]!=0) cand_f[tab[w][j]-1]=0;
if (tab[i][w]!=0) cand_f[tab[i][w]-1]=0;
}
for (int w=0;w<dim;w++)
if (cand_f[w]!=0)
*num_cand+=1;
if (*num_cand==1) {
*x=i;
*y=j;
int z=0;
for (int w=0;w<dim;w++)
if (cand_f[w]!=0) {
cand[z]=w+1;
z++;
}
return true;
}
else if (*num_cand<min && *num_cand>0) {
int z=0;
for (int w=0;w<dim;w++)
if (cand_f[w]!=0) {
cand[z]=w+1;
z++;
}
min=*num_cand;
*x=i;
*y=j;
}
else if (*num_cand==0) {
return false;
}
}
}
*num_cand=min;
if (free<1) return false;
else return true;
}
bool Fsudoku(int tab[dim][dim]) {
int free=0;
int x,y;
int cand[dim];
int num_cand;
brojacK=0;
if (!Fsearch(tab,&x,&y,cand, &num_cand,free)) {
if (free==0) return true;
else return false;
}
for (int i=0;i<num_cand;i++) {
tab[x][y]=cand[i];
if (Fsudoku(tab)) return true;
else tab[x][y]=0;
}
return false;
}
Can someone tell help me classify this algorithm in Big O or Big Theta notation. I got O(n^3) but as we can see that's not true! So, give me a tip or an advice how to start, I would be very thankful.
And if you like, I can post this in pseudo-code too!
Thanks,
MB
Big O is about which terms dominate.
So how many times do each of the loops run?
Are they of fixed length, or do they vary?
What parameters can change that would effect the run time?
Ive tried to create my own implementation of a bignum library
I cant seem to get the factorial to work. If I ask it to solve 4!, it gives out 96. It multiplies 4 twice. similarly, 5! is 600, not 120. I haven't implemented division, so I cant/dont want to divide the answer by the number
//bignum project
#include <iostream>
using namespace std;
class bignum
{
public:
int number[100];
int dpos;
int operator/ (bignum);
bignum operator- (bignum);
bignum operator* (bignum);
bignum operator+ (bignum);
bignum operator= (string);
void output()
{
int begin=0;
for(int i=0; i<=99; i++)
{
if(number[i]!=0 || begin==1)
{
cout<<number[i];
begin=1;
}
}
}
};
bool num_is_zero(bignum k)
{
for(int a=0; a<=99; a++)
{
if(k.number[a]!=0)
{
return false;
}
}
return true;
}
bignum factorial(bignum a)
{
bignum j;
bignum fact;
fact="1";
while(!num_is_zero(a))
{
j="1";
fact=fact*a;
a=a-j;
}
return fact;
}
bignum bignum::operator= (string k)
{
int l;
l=k.length()-1;
for(int h=0; h<=99; h++)
{
number[h]=0;
}
for(int a=99; a>=0 && l>=0; a--)
{
number[a]=k[l]-'0';
l--;
}
}
bignum bignum::operator+ (bignum b)
{
bignum a;
int carry=0;
for(int k=0; k<=99; k++)
{
a.number[k]=0;
}
for(int i=99; i>=0; i--)
{
a.number[i]= number[i]+b.number[i]+a.number[i];
if(a.number[i]>9)
{
carry=(a.number[i]/10);
a.number[i-1]+=carry;
a.number[i]=(a.number[i]%10);
}
}
return (a);
}
bignum bignum::operator- (bignum c)
{
bignum a;
int sign=0;
for(int k=0; k<=99; k++)
{
a.number[k]=0;
}
for(int i=99; i>=0; i--)
{
if(number[i]<c.number[i])
{
number[i]+=10;
if(i!=0)
number[i-1]--;
}
a.number[i]=number[i]-c.number[i];
}
return (a);
}
bignum bignum::operator* (bignum b)
{
bignum ans;
int ans_grid[100][100],x,lines=0,carry,sum[100];
for(int a=0; a<=99; a++)
{
for(int b=0; b<=99; b++)
{
ans_grid[a][b]=0;
}
}
for(int i=99; i>=0; i--)
{
for(int j=i,x=99; j>=0; j--,x--)
{
ans_grid[lines][j]=(number[i]*b.number[x]);
}
lines++;
}
//------------------------------------------------Carry Forward and assign to ans------------------------------------------------//
for(int j=99; j>=0; j--)
{
for(int i=99; i>=0; i--)
{
if(ans_grid[j][i]>9 && i!=0)
{
carry=(ans_grid[j][i]/10);
ans_grid[j][i-1]+=carry;
ans_grid[j][i]%=10;
}
}
}
for(int col=99; col>=0; col--)
{
for(int row=99; row>=0; row--)
{
sum[col]+=ans_grid[row][col];
}
}
for(int i=99; i>=0; i--)
{
if(sum[i]>9 && i!=0)
{
carry=(sum[i]/10);
sum[i-1]+=carry;
sum[i]%=10;
}
}
for(int l=0; l<=99; l++)
ans.number[l]=sum[l];
//-------------------------------------------------------------------------------------------------------------------------------//
return (ans);
}
I think your problem is that sum is uninitialized in your operator*. I'm reluctant to give a partial answer, since I took the code and fiddled with it a bit, so here's my version which appears to work (and also prints "0" correctly):
Update: I couldn't resist making several structural improvements. I didn't touch your multiplication routine, so you should still be able to extract the bugfix even if you don't care for the rest.
#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
class bignum
{
public:
int number[100];
bignum() { std::fill(number, number + 100, 0); }
bignum(const bignum & other) { std::copy(other.number, other.number + 100, number); }
bignum(const std::string &);
bignum & operator-=(const bignum &);
inline bignum operator-(const bignum & c) const { return bignum(*this) -= c; }
bignum operator*(const bignum &) const;
inline bignum & operator= (const std::string & k) { return *this = bignum(k); }
inline operator bool() const
{
for (size_t a = 0; a < 100; ++a)
if (number[a] != 0) return true;
return false;
}
};
std::ostream & operator<<(std::ostream & o, const bignum & b)
{
bool begun = false;
for (size_t i = 0; i < 100; ++i)
{
if (begun || b.number[i] != 0)
{
cout << b.number[i];
begun = true;
}
}
if (!begun) o << "0";
return o;
}
bignum::bignum(const std::string & k)
{
std::fill(number, number + 100, 0);
for(size_t h = 0; h < std::min(k.length(), 100U); ++h)
number[99 - h] = k[k.length() - 1 - h] - '0';
}
bignum & bignum::operator-=(const bignum & c)
{
for (int i = 99; i >= 0; --i)
{
if (number[i] < c.number[i])
{
number[i] += 10;
if (i != 0) --number[i-1];
}
number[i] -= c.number[i];
}
return *this;
}
bignum bignum::operator*(const bignum & b) const
{
bignum ans;
int ans_grid[100][100], lines = 0, carry, sum[100];
std::fill(sum, sum + 100, 0);
for (size_t i = 0; i < 100; ++i) std::fill(ans_grid[i], ans_grid[i] + 100, 0);
for(int i=99; i>=0; i--)
{
for(int j=i,x=99; j>=0; j--,x--)
{
ans_grid[lines][j]=(number[i]*b.number[x]);
}
lines++;
}
//------------------------------------------------Carry Forward and assign to ans------------------------------------------------//
for(int j=99; j>=0; j--)
{
for(int i=99; i>=0; i--)
{
if(ans_grid[j][i]>9 && i!=0)
{
carry=(ans_grid[j][i]/10);
ans_grid[j][i-1]+=carry;
ans_grid[j][i]%=10;
}
}
}
for(int col=99; col>=0; col--)
{
for(int row=99; row>=0; row--)
{
sum[col]+=ans_grid[row][col];
}
}
for(int i=99; i>=0; i--)
{
if(sum[i]>9 && i!=0)
{
carry=(sum[i]/10);
sum[i-1]+=carry;
sum[i]%=10;
}
}
for(int l=0; l<=99; l++)
ans.number[l]=sum[l];
//-------------------------------------------------------------------------------------------------------------------------------//
return (ans);
}
bignum factorial(bignum a)
{
bignum j; j = "1";
bignum fact; fact="1";
while(a)
{
fact = fact * a;
a = a-j;
}
return fact;
}
int main(int argc, char * argv[])
{
if (argc < 2) return 0;
bignum a;
a = std::string(argv[1]);
bignum b = factorial(a);
cout << a << std::endl << b << std::endl;
}
The string assignment is still broken for strings with more than one digit, but that wasn't your question I suppose...