The Problem: Given an N by M Matrix, Create an Anti-Clockwise Traversal Path that winds in all the way into the Matrix
Example: The Matrix is 9 by 5
Output:
| 1|| 24|| 23|| 22|| 21|
| 2|| 25|| 40|| 39|| 20|
| 3|| 26|| 41|| 38|| 19|
| 4|| 27|| 42|| 37|| 18|
| 5|| 28|| 43|| 36|| 17|
| 6|| 29|| 44|| 35|| 16|
| 7|| 30|| 45|| 34|| 15|
| 8|| 31|| 32|| 33|| 14|
| 9|| 10|| 11|| 12|| 13|
Code:
package com.progint;
import java.io.IOException;
import java.security.SecureRandom; /*For Maximum-Entropy Goodness*/
public class DerLooper {
static final int xMax=20, yMax=20, xMin=1, yMin=1; /* Maximum and Minimum Matrix Size */
static int xCord, yCord;
static SecureRandom randomGenerator = new SecureRandom();
static int[][] looper;
DerLooper() {
xCord= xMin+randomGenerator.nextInt(xMax-xMin); yCord=yMin+randomGenerator.nextInt(yMax-yMin);
looper = new int[xCord][yCord];
}
/*
* ________left__________
* | |
* down up
* |_______right_________|
*
* right eats higher row
* up eats higher column
* left eats lower row
* down eats lower column
*
*/
static void displayLooper() {
int pathNumber=1;
int currentX=0, currentY=0;
int lowerColumn=0, lowerRow=0;
int higherColumn=yCord, higherRow=xCord;
while(true) {
//Go Down if Possible
/*
* 0
* 0 [1]
* 1 [2]
* 2 [3]
* 3 [4]
* higherColumn,lowerColumn=0 | lowerRow=0,higherRow=3
*/
while(currentX<higherRow) {
looper[currentX++][currentY] = pathNumber++;
}
if(lowerColumn+1<higherColumn) {lowerColumn++;} //eats lower column
else if (lowerColumn+1>=higherColumn) {break;}
//Go Right if Possible
/*
* 0 1 2 3 4
* 0 [1]
* 1 [2]
* 2 [3]
* 3 [4][5][6][7][8]
* higherColumn=4,lowerColumn=1 | lowerRow=0,higherRow=3
*/
currentX--;
currentY++;
while(currentY<higherColumn) {
looper[currentX][currentY++] = pathNumber++;
}
if(higherRow-1>lowerRow) {higherRow--;} //eats higher row
else if (higherRow-1<=lowerRow) {break;}
//Go Up if Possible
/*
* 0 1 2 3 4
* 0 [1] [11]
* 1 [2] [10]
* 2 [3] [9]
* 3 [4][5][6][7][8]
* higherColumn=4,lowerColumn=1 | lowerRow=0,higherRow=2
*/
currentX--;
currentY--;
while(currentX>=lowerRow) {
looper[currentX--][currentY] = pathNumber++;
}
if(higherColumn-1>lowerColumn) {higherColumn--;} //eats higher column
else if (higherColumn-1<=lowerColumn) {break;}
//Go Left if Possible
/*
* 0 1 2 3 4
* 0 [1] [14][13][12] [11]
* 1 [2] [10]
* 2 [3] [9]
* 3 [4] [5] [6] [7] [8]
* higherColumn=3,lowerColumn=1 | lowerRow=0,higherRow=2
*/
currentX++;
currentY--;
while(currentY>=lowerColumn) {
looper[currentX][currentY--] = pathNumber++;
}
if(lowerRow+1<higherRow) {lowerRow++;} //eats lower row
else if (lowerRow+1>=higherRow) {break;}
//Loop through next subMatrix
/*
* 0 1 2 3 4
* 0 [1] [14][13][12] [11]
* 1 [2] here [10]
* 2 [3] [9]
* 3 [4] [5] [6] [7] [8]
* higherColumn=3,lowerColumn=1 | lowerRow=1,higherRow=2
*/
currentX++;
currentY++;
}
System.out.println("The Matrix is "+xCord+" by "+yCord+"\n");
for (int i=0; i<xCord; i++) {
for (int j=0; j<yCord; j++) {
System.out.printf("|%3d|",looper[i][j]);
}
System.out.println();
}
}
public static void main(String[] args) throws NumberFormatException, IOException {
new DerLooper();
displayLooper();
}
}
