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 ] ]
此题跟之前那道本质上没什么区别，就相当于个类似逆运算的过程，这道题是要按螺旋的顺序来填数，由于给定矩形是个正方形，我们计算环数时用n / 2来计算，若n为奇数时，注意一下中间点。
class Solution { public: vector<vector<int>> generateMatrix(int n) { vector<vector<int>> v(n,vector<int>(n,1)); int cnt = 1; int p=n; for (int i=0; i<n/2; i++, p=p-2){ for(int col=i; col < i+p; col ++){ v[i][col] = cnt++; } for(int row=i+1; row < i+p; row++){ v[row][i+p-1] = cnt++; } for(int col=i+p-2; col>=i; col--){ v[i+p-1][col] = cnt++; } for(int row=i+p-2; row>i; row--){ v[row][i] = cnt++; } } if((n%2) == 1)v[n/2][n/2] = cnt; return v; } };
