LeetCode59 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: （Medium）

[
 [ 1, 2, 3 ],
 [ 8, 9, 4 ],
 [ 7, 6, 5 ]
]

分析：

跟 Sprial Matrix I处理方式一样，先建立好n * n的数组，然后按照顺时针顺序填入数字即可。

代码：

 class Solution {
 public:
     vector<vector<int>> generateMatrix(int n) {
         vector<vector<int>> result(n, vector<int>(n,));
         int rowBegin = , rowEnd = n - , colBegin = , colEnd = n - ;
         int count = ;
         while (rowBegin <= rowEnd && colBegin <= colEnd) {
             for (int i = colBegin; i <= colEnd; ++i ) {
                 result[rowBegin][i] = count;
                 count++;
             }
             rowBegin++;
             if (rowBegin > rowEnd) {
                 break;
             }
             for (int i = rowBegin; i <= rowEnd; ++i) {
                 result[i][colEnd] = count;
                 count++;
             }
             colEnd--;
             if (colBegin > colEnd) {
                 break;
             }
             for (int i = colEnd; i >= colBegin; --i) {
                 result[rowEnd][i] = count;
                 count++;
             }
             rowEnd--;
             if (rowBegin > rowEnd) {
                 break;
             }
             for (int i = rowEnd; i>= rowBegin; --i) {
                 result[i][colBegin] = count;
                 count++;
             }
             colBegin++;
         }
         return result;
     }
 };