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 ] ]
写一个回旋的矩阵
class Solution {
public:
vector<vector<int> > generateMatrix(int n) {
vector<vector<int> >re;
for(int i = 0 ;i < n; i++)
{
vector <int> temp(n,0);
re.push_back(temp);
}
int direction =0; //0 right ,1 down ,2 left, 3 up
int length = n;
int x = 0;
int y = 0;
int step = 0;
for(int i = 1 ; i <= n*n ; i++)
{
re[x][y] = i;
step++;
if(step == length) //should turn
{
direction = (direction + 1)%4;
if(direction == 0)
{
y = y+1;
step = 0;
}
else if(direction == 1)
{
x = x+1;
length--;
step = 0;
}
else if(direction == 2)
{
y = y-1;
step = 0;
}
else
{
x = x-1;
length--;
step = 0;
}
}
else
{
if(direction == 0) y = y+1;
else if(direction == 1)x = x+1;
else if(direction == 2)y = y-1;
else x = x-1;
}
}
return re;
}
};
Spiral Matrix II,布布扣,bubuko.com
原文：http://www.cnblogs.com/pengyu2003/p/3595609.html