package javaapplication3;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.StringTokenizer;
/**
* By starting at the top of the triangle below and moving to adjacent numbers
* on the row below, the maximum total from top to bottom is 23.
*
* 3
* 7 4
* 2 4 6
* 8 5 9 3
*
* That is, 3 + 7 + 4 + 9 = 23.
*
* Find the maximum total from top to bottom of the triangle below:
*
* 75
* 95 64
* 17 47 82
* 18 35 87 10
* 20 04 82 47 65
* 19 01 23 75 03 34
* 88 02 77 73 07 63 67
* 99 65 04 28 06 16 70 92
* 41 41 26 56 83 40 80 70 33
* 41 48 72 33 47 32 37 16 94 29
* 53 71 44 65 25 43 91 52 97 51 14
* 70 11 33 28 77 73 17 78 39 68 17 57
* 91 71 52 38 17 14 91 43 58 50 27 29 48
* 63 66 04 68 89 53 67 30 73 16 69 87 40 31
* 04 62 98 27 23 09 70 98 73 93 38 53 60 04 23
*
* NOTE: As there are only 16384 routes, it is possible to solve this problem by
* trying every route. However, Problem 67, is the same challenge with a
* triangle containing one-hundred rows; it cannot be solved by brute force, and
* requires a clever method! ;o)
*/
/**
*
* @author Umang
*/
public class Problem18
{
/**
* get the file content from given location
* @return file content in string format
*/
private static String getFileContent()
{
StringBuilder content = new StringBuilder("");
File aFile = new File("D:/input.txt");
Scanner aScanner = null;
try
{
aScanner = new Scanner(aFile);
}
catch (FileNotFoundException ex)
{
System.out.println("File could not be readed");
ex.printStackTrace();;
System.exit(0);
}
while (aScanner.hasNextLine())
{
content = content.append(aScanner.nextLine() + "\n");
}
return content.toString();
}
/**
* gets the numbers in format of LinkedList<LinkedList<Integer>>
* @return LinkedList<LinkedList<Integer>> from the ifile
*/
private static LinkedList<LinkedList<Integer>> getList()
{
LinkedList<LinkedList<Integer>> result = new LinkedList< LinkedList< Integer>>();
String content = getFileContent();
StringTokenizer lineTokenizer = new StringTokenizer(content, "\n\r");
while (lineTokenizer.hasMoreTokens())
{
LinkedList<Integer> row = new LinkedList<Integer>();
StringTokenizer numberTokenizer = new StringTokenizer(lineTokenizer.nextToken(), " ");
while (numberTokenizer.hasMoreTokens())
{
Integer no = new Integer(numberTokenizer.nextToken());
row.add(no);
}
result.add(row);
}
return result;
}
/**
*
* @param rows is the LinkedList<LinkedList<Integer>> where everything is stored
* @param row_no is the row number
* @param col_no is the column number
* @return the actual number at given row and column from LinkedList<LinkedList<Integer>>
* @throws Exception if no number is found in the list (assuming that the
* number is never 0 in the list)
*/
public static int get_item_at(LinkedList<LinkedList<Integer>> rows, int row_no, int col_no) throws Exception
{
int no = 0;
int row_count = 0;
int col_count = 0;
for (LinkedList<Integer> row : rows)
{
col_count = 0;
for (Integer number : row)
{
if (row_no == row_count && col_count == col_no)
{
no = number;
break;
}
col_count++;
}
row_count++;
}
if (no == 0)
{
throw new Exception("No such item");
}
return no;
}
public static void main(String[] args) throws Exception
{
LinkedList<LinkedList<Integer>> numbers = getList();
System.out.println("Ans is " + getHighestSumFromList(numbers, 0, 0));
}
private static int getHighestSumFromList(LinkedList<LinkedList<Integer>> rows, int row, int col) throws Exception
{
int currunt_no = get_item_at(rows, row, col);
int mul_left = 0;
int mul_right = 0;
try
{
mul_left = getHighestSumFromList(rows, row + 1, col) + currunt_no;
mul_right = getHighestSumFromList(rows, row + 1, col + 1) + currunt_no;
}
catch (Exception e)
{
// if at the end of the list then return the currunt value
return get_item_at(rows, row, col);
}
int bigger_number = mul_left > mul_right ? mul_left : mul_right;
return bigger_number;
}
}
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