Here is the solution of simple algorithmic task – generation of integer sequences. There is a some challenge (easy level) at the site codenirvana.in :

CHALLENGE DESCRIPTION:
Write a program that prints out the pattern generated according to the input (number) from the user.
Pattern input and output sample is given below, check the input and the following pattern generated for that condition (number). Make sure you program follow the same pattern logic for every input.

INPUT SAMPLE:
Your program should ask for a number F first and than print the pattern accordingly. E.g.

Enter a number: 4

OUTPUT SAMPLE:
For the input N=4 output will be

4444444
4333334
4322234
4321234
4322234
4333334
4444444

Here is my solution (“С” for Windows). I’ve implemented two sequences generators – iterative and recursive:

// lines_gen.cpp : Defines the entry point for the console application.
//

#include <stdio.h>
#include <tchar.h>
#include <windows.h>

VOID init_line                          (PUINT	punLine, UINT unN);
VOID print_line                         (PUINT	punLine, UINT unN);
UINT proc_elem                          (PUINT	punLine, UINT unN, UINT unIdx);
UINT proc_array_rec                     (PUINT	punLine, UINT unN);
UINT proc_array_iter                    (PUINT	punLine, UINT unN);
UINT proc_array_iter_bak                (PUINT	punLine, UINT unN);

VOID init_line(PUINT	punLine, UINT unN)
{
  UINT unIdx;
  for(unIdx = 0; unIdx < unN; unIdx++)
    punLine[unIdx] = unIdx+1;
}

VOID print_line(PUINT	punLine, UINT unN)
{
  UINT unIdx;
  _tprintf(_T("line = "));
  for(unIdx = 0; unIdx < unN; unIdx++)
    _tprintf(_T("%d "),punLine[unIdx]);
  _tprintf(_T("\n"));
  return;
}

UINT proc_elem(PUINT	punLine, UINT unN, UINT unIdx)
{
  UINT unRes = 0;

  if((unIdx + 1) >= unN)
    return 0;

  if(punLine[unIdx] >= punLine[unIdx+1])
    unRes = proc_elem(punLine, unN, unIdx+1);
  else
    unRes = punLine[unIdx+1];

  if(unRes)
  {
    punLine[unIdx] = unRes;
    return punLine[unIdx];
  }
  else
    return 0;
}

UINT proc_array_rec(PUINT	punLine, UINT unN)
{
  UINT unCount = 0;

  print_line(punLine, unN);
  while(TRUE)
  {
    unCount++;
    if(!proc_elem	(punLine, unN, 0))
      break;
    print_line(punLine, unN);
  }

  return unCount;
}

UINT proc_array_iter(PUINT punLine, UINT unN)
{
  UINT unIdx;
  UINT unIdxIn;

  print_line(punLine, unN);
  for(unIdx = 1; unIdx < unN; unIdx++)
  {
    for(unIdxIn = 0; unIdxIn <= unIdx; unIdxIn++)
      punLine[unIdxIn] = unIdx+1;
    print_line(punLine, unN);
  }
  return unIdx;
}

UINT proc_array_iter_bak(PUINT punLine, UINT unN)
{
  UINT unIdx;
  UINT unIdxIn;

  print_line(punLine, unN);
  for(unIdx = 1; unIdx < unN; unIdx++)
  {
    UINT unBackIdx = unN-unIdx;
    for(unIdxIn = 0; unIdxIn <= (unBackIdx-1); unIdxIn++)
      punLine[unIdxIn] = unBackIdx;
    print_line(punLine, unN);
  }
  return unIdx;
}

INT _tmain(int argc, _TCHAR* argv[])
{
  UINT	unN		= 0;
  PUINT	punLine	= NULL;
  UINT	unCount;

  _tprintf(_T("Enter a number : "));
  _tscanf_s(_T("%d"), &unN);

  if(!unN)
    return 0;

  punLine = (PUINT) malloc(unN*sizeof(UINT));

  init_line(punLine, unN);
  unCount = proc_array_iter(punLine, unN);
  _tprintf(_T("Total count = %d\n"), unCount);
  _tprintf(_T("-----------------\n"));
  unCount = proc_array_iter_bak(punLine, unN);
  _tprintf(_T("Total count = %d\n"), unCount);
  _tprintf(_T("-----------------\n"));
  unCount = proc_array_rec(punLine, unN);
  _tprintf(_T("Total count = %d\n"), unCount);

  free(punLine);

  return 0;
}

Output:

Enter a number : 5
line = 1 2 3 4 5
line = 2 2 3 4 5
line = 3 3 3 4 5
line = 4 4 4 4 5
line = 5 5 5 5 5
Total count = 5
-----------------
line = 5 5 5 5 5
line = 4 4 4 4 5
line = 3 3 3 4 5
line = 2 2 3 4 5
line = 1 2 3 4 5
Total count = 5
-----------------
line = 1 2 3 4 5
line = 2 2 3 4 5
line = 3 3 3 4 5
line = 4 4 4 4 5
line = 5 5 5 5 5
Total count = 5

lines_gen.c
output.txt

Java:

/**
 * 
 */
package com.smansoft;

/**
 * @author SMan
 * 
 */
public class LinesGen {

  /**
   * 
   */
  int line[] = null;
  
  /**
   * @param args
   */
  public static void main(String[] args) {
    int inNum = Integer.parseInt(args[0]);		
    
    System.out.printf("Number = %d\n", inNum);

    LinesGen linesGen = new LinesGen(inNum);
    linesGen.initLine();

    int count = linesGen.procArrayIter();
    System.out.printf("Total count = %d\n", count);
    count = linesGen.procArrayIterBak();
    System.out.printf("Total count = %d\n", count);
    count = linesGen.procArrayRec();
    System.out.printf("Total count = %d\n", count);
  }

  /**
   * 
   * @param size
   */
  public LinesGen(int size) {
    line = new int[size];
  }

  /**
   * 
   */
  public void initLine() {
    for (int idx = 0; idx < line.length; idx++) {
      line[idx] = (idx + 1);
    }
  }

  /**
   * 
   */
  public void printLine() {
    System.out.print("line = ");
    for (int idx = 0; idx < line.length; idx++) {
      System.out.printf("%d ", line[idx]);
    }
    System.out.println("");
  }

  /**
   * 
   * @return
   */
  public int procArrayRec() {
    int count = 0;
    printLine();
    while (true) {
      count++;
      if (procElem(0) == 0)
        break;
      printLine();
    }
    return count;
  }

  /**
   * 
   * @return
   */
  public int procArrayIter() {
    int idx;
    printLine();
    for (idx = 1; idx < line.length; idx++) {
      for (int idxIn = 0; idxIn <= idx; idxIn++) {
        line[idxIn] = idx + 1;
      }
      printLine();
    }
    return idx;
  }

  /**
   * 
   * @return
   */
  public int procArrayIterBak() {
    int idx;
    printLine();
    for (idx = 1; idx < line.length; idx++) {
      for (int idxIn = 0; idxIn <= (line.length - idx - 1); idxIn++) {
        line[idxIn] = line.length - idx;
      }
      printLine();
    }
    return idx;
  }
  
  /**
   * 
   * @param idx
   * @return
   */
  private int procElem(int idx) {
    int res = 0;

    if ((idx + 1) >= line.length)
      return 0;

    if (line[idx] >= line[idx + 1])
      res = procElem(idx + 1);
    else
      res = line[idx + 1];

    if (res > 0) {
      line[idx] = res;
      return line[idx];
    } else
      return 0;
  }
}

Output (ant run.LinesGen):

run.LinesGen:
[java] Number = 5
[java] line = 1 2 3 4 5
[java] line = 2 2 3 4 5
[java] line = 3 3 3 4 5
[java] line = 4 4 4 4 5
[java] line = 5 5 5 5 5
[java] Total count = 5
[java] line = 5 5 5 5 5
[java] line = 4 4 4 4 5
[java] line = 3 3 3 4 5
[java] line = 2 2 3 4 5
[java] line = 1 2 3 4 5
[java] Total count = 5
[java] line = 1 2 3 4 5
[java] line = 2 2 3 4 5
[java] line = 3 3 3 4 5
[java] line = 4 4 4 4 5
[java] line = 5 5 5 5 5
[java] Total count = 5

LinesGen.java
LinesGen.zip (including ant script)
joutput.txt