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p59

admin 11月 12, 2020 0

LeetCode p59 Spiral Matrix II 题解

1.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 ]
]

题意：

输入一个数n，返回n*n的数组，内容是1-n的螺旋排列。

2.解题思路:

见代码TUT。。暴力了一波。

3.代码

[title] [] [url] [link text]

 
public class  {
    public int[][] generateMatrix(int n) {
        int sum = n * n;
		int i=0;
		int j=0;
		int[][] ans = new int[n][n];
		for (int k = 1; k <= sum; ) {

			while (i<n)
			{
				if (ans[j][i]!=0) break;
				ans[j][i]=k;
				
				k++;
				i++;
			}
			i--;
			j++;
			while (j<n)
			{
				if (ans[j][i]!=0) break;
				ans[j][i]=k;
				
				k++;
				j++;
			}
			i--;
			j--;
			while (i>-1)
			{
				if (ans[j][i]!=0) break;
				ans[j][i]=k;
				
				k++;
				i--;
			}
			i++;
			j--;
			while (j>-1)
			{
				//System.out.println(i+"   "+j);
				if (ans[j][i]!=0) break;
				
				ans[j][i]=k;
				k++;
				j--;
			}
			i++;
			j++;
			//System.out.println(i+"   "+j);
		}
		return ans;
    }
}

4.一些总结：