Leetcode59 Spiral Matrix II
Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. For example,
Given n =
Given n =
3,
You should return the following matrix:
[ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ] ]
回型打印整数n。
Tips: dr dc控制指针的走向，当不满足
(newRow>=0 && newRow<n && newCol>=0 && newCol<n && !visit[newRow][newCol])这些条件时，指针就要改变方向。
package medium; public class L59SpiralMatrixII { public int[][] generateMatrix(int n) { int[][] ans = new int[n][n]; boolean[][] visit = new boolean[n][n]; int row = 0; int col = 0; int ind = 0; int[] dr = { 0, 1, 0, -1 }; int[] dc = { 1, 0, -1, 0 }; for (int i = 0; i < n * n; i++) { ans[row][col] = i + 1; visit[row][col] = true; int newRow=row+dr[ind]; int newCol=col+dc[ind]; if(newRow>=0 && newRow<n && newCol>=0 && newCol<n && !visit[newRow][newCol]){ row=newRow; col=newCol; }else{ ind=(ind+1)%4; row+=dr[ind]; col+=dc[ind]; } } return ans; } public void print(int[][] ans,int n){ for(int i=0;i<n;i++){ for(int j=0;j<n;j++){ System.out.print(ans[i][j]+" "); } System.out.println(); } } public static void main(String[] args) { L59SpiralMatrixII cc= new L59SpiralMatrixII(); int n=4; int[][] ans= cc.generateMatrix(n); cc.print(ans, n); } }
