Leetcode Spiral Matrix II

题意：输出旋转递增矩阵。

思路：简单模拟，注意边界条件。

class Solution {
public:
    vector<vector<int> > re;
    int l;
    vector<vector<int>> generateMatrix(int n) {
        l = n - 1;
        vector<int> temp(n, 0);
        for(int i = 0; i < n; ++ i) re.push_back(temp);
        int s = 1;
        for(int i = 0; i < ceil(n / 2.0); i ++) {
            s = sprial(s, i, n - 2 * i);
        }
        
        return re;
        
        
    }
    int sprial(int s,int n, int len) {
        if(len == 1) {
            re[n][n] = s;
            return ++ s;
        }
        
        for(int i = n; i < l - n; i ++) {
            re[n][i] = s;
            s ++;
        }
        
        for(int i = n; i < l - n; ++ i) {
            re[i][l - n] = s;
            s ++;
        }
        for(int i = l - n; i > n; -- i) {
            re[l - n][i] = s;
            s ++;
        }
        for(int i = l - n; i > n; -- i) {
            re[i][n] = s;
            s ++;
        }
        return s;
    }
};