59. 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:[ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ]]

解析

class Solution_59 {public:    vector
    
     
       > generateMatrix(int n) {        vector
      
       
        > vecs(n, vector
        
         (n,1));                int x0 = 0, y0 = 0;        int x1 = n - 1, y1 = n - 1;        int index = 0;        while (x0<=x1&&y0<=y1)        {            for (int i = y0; i <= y1;i++)            {                vecs[x0][i] = ++index;            }            for (int i = x0 + 1; i <= x1;i++)            {                vecs[i][y1] = ++index;            }            for (int i = y1 - 1; i >= y0;i--)            {                vecs[x1][i] = ++index;            }            for (int i = x1 - 1; i > x0;i--)            {                vecs[i][y0] = ++index;            }            x0++, y0++;            x1--, y1--;        }                return vecs;    }};
        
       
      
     
    

题目来源