leetcode 59. 螺旋矩阵 II

题目描述

代码：

class Solution {
public:
    vector<vector<int>> generateMatrix(int n) {
        vector<vector<int>> res(n,vector<int>(n,0));
        int num = 1;
        int len = n;
        int start = 0;
        while(len > 0){
            int row = start;
            int column = start;
            if(len==1){
                res[row][column] = num++;
                break;
            }
            start++;
            for(int i =0;i < len-1;i++){
                res[row][column++] = num++;
            }
            for(int i = 0;i < len-1;i++){
                res[row++][column] = num++;
            }
            for(int i = 0;i < len-1;i++){
                res[row][column--] = num++;
            }
            for(int i = 0;i < len-1;i++){
                res[row--][column] = num++;
            }
            len-=2;
        }
        return res;
    }
};