# Spiral Matrix II

Spiral Matrix II array

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.

``````For example,
Given n = 3,

You should return the following matrix:
[[ 1, 2, 3 ],
[ 8, 9, 4 ],
[ 7, 6, 5 ]]
``````

Spiral Matrix Ii Solution

``````public class SpiralMatrix {
public int[][] generateMatrix(int n) {
int[][] spiral = new int[n][n];

if(n == 0) {
return spiral;
}

int rowStart = 0;
int colStart = 0;
int rowEnd = n - 1;
int colEnd = n -1;
int number = 1;

while(rowStart <= rowEnd && colStart <= colEnd) {
for(int i = colStart; i <= colEnd; i++) {
spiral[rowStart][i] = number++;
}

rowStart++;

for(int i = rowStart; i <= rowEnd; i++) {
spiral[i][colEnd] = number++;
}

colEnd--;

for(int i = colEnd; i >= colStart; i--) {
if(rowStart <= rowEnd) {
spiral[rowEnd][i] = number++;
}
}

rowEnd--;

for(int i = rowEnd; i >= rowStart; i--) {
if(colStart <= colEnd) {
spiral[i][colStart] = number++;
}
}

colStart++;
}

return spiral;
}
}``````