Spiral Matrix II

题目：

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 ]
]

CPP:

class Solution {
public:
vector<vector<int>> generateMatrix(int x) {
vector<vector<int>> result;
if (x == 0) {
return result;
} else {
vector<int> v(x);
for (int i = 0; i < x; i++) {
result.push_back(v);
}
}

int r = 0; //第几圈
int i;
//left to right
int a = 1;
while (r < x / 2) {
for (i = r; i < x - r; i++) {
result[r][i] = a;
a++;
}
//up to down
for (i = r + 1; i < x - r ; i++) {
result[i][x - r-1] = a;
a++;
}
//right to left
for (i = x - r - 2; i >= r; i--) {
result[x - r-1][i] = a;
a++;
}
//down to up
for (i = x - r - 2; i > r; i--) {
result[i][r] = a;
a++;
}
r++;
}
if(2*r !=x)
{
result[r][r] = a;
}
return result;
}
};

　python:

class Solution(object):
def generateMatrix(self,n):
ans = []
for x in range(n):
ans.append([0]*n)
mini,minj,maxi,maxj = 0,0,n-1,n-1
num = 1

while maxi >= mini and maxj >= minj:
#left to right
for j in range(minj,maxj+1):
ans[minj][j] = num
num +=1
mini += 1
#up to down
for i in range(mini,maxi+1):
ans[i][maxj] = num
num +=1
maxj -= 1
#right to left
for j in range(maxj,minj-1,-1):
ans[maxi][j] = num
num +=1
maxi -=1
#down to up
for i in range(maxi,mini-1,-1):
ans[i][minj] = num
num +=1
minj += 1
return ans;