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 ]]问题描述：给定一个整数n，生成一个方阵，它含有从1到n^2的元素，而且这些整数以向中间旋转的方式排列。我采用的是最笨的办法，先来看外面一圈是如何计算的，第0行，从0～2依次是1～3，然后是第2列，第1个是4，然后是第2行，从2～0依次是5～7，然后是第0列，第1个是8。

class Solution {public:    vector
    
     
       > generateMatrix(int n) {        // Note: The Solution object is instantiated only once and is reused by each test case.        vector
      
       
         > vec(n, vector
        
         (n));                int i = 0, j = 0;        int count = 1;        int index = 0;        int start = 0, end = n-1;        while(count <= n*n) {            for(i = index, j = start; j <= end && count <= n*n; j++)                vec[i][j] = count++;            for(j = n-1-index, i = start+1; i < end && count <= n*n; i++)                vec[i][j] = count++;             for(i = n-1-index, j = end; j >= start && count <= n*n; j--)                vec[i][j] = count++;             for(j = index, i = end-1; i >= start+1 && count <= n*n; i--)                vec[i][j] = count++;            index++;            start++;            end--;        }        return vec;      }};