原题链接:https://leetcode.com/problems/spiral-matrix-ii/
思路和上篇的螺旋矩阵一样,用两个一维数组控制方向,
用一个Boolean数组判断是否访问过,然后更新 i , j的值。
AC 1ms 100% Java:
class Solution {
public int[][] generateMatrix(int n) {
int[][] ans=new int[n][n];
boolean[][] visit=new boolean[n][n];
int[] directR={0,1,0,-1};
int[] directC={1,0,-1,0};
int i=0,j=0;
int d=0;
for(int temp=1;temp<=n*n;temp++){
visit[i][j]=true;
ans[i][j]=temp;
int row=i+directR[d];
int col=j+directC[d];
if(row>=0&&row<n&&col>=0&&col<n&&!visit[row][col]){
i=row;
j=col;
}else{
d=(d+1)%4;
i+=directR[d];
j+=directC[d];
}
}
return ans;
}
}