[leetcode]59. Spiral Matrix II

Analysis

intern intern intern—— [每天刷題並不難0.0]

Given a positive integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.

Implement

class Solution {
public:
    vector<vector<int>> generateMatrix(int n) {
        vector<
 
vector<int>> res(n, vector<int>(n));
        int k = 1;
        int i = 0;
        while(k <= n*n){
            int j = i;
            while(j < n - i)
                res[i][j++] = k++;
            j = i + 1;
            while(j < n - i)
                res[j++][n-i-1] = k++;
 

            j = n-i-2;
            while(j > i)
                res[n-i-1][j--] = k++;
            j = n-i-1;
            while(j > i)
                res[j--][i] = k++;
            i++;
        }
        return res;
    }
};