题目描述
输入一个矩阵,按照从外向里以顺时针的顺序依次打印出每一个数字,例如,如果输入如下4 X 4矩阵: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 则依次打印出数字1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10.
代码
public class Solution19 {
public ArrayList<Integer> printMatrix(int[][] matrix) {
ArrayList<Integer> res = new ArrayList<>();
int row = matrix.length;//行数
int collor = matrix[0].length;//列数
//计算打印的圈数
int circle = ((row < collor ? row : collor) - 1) / 2 + 1;//圈数
for (int i = 0; i < circle; i++) {
//从左向右打印
for (int j = i; j < collor - i; j++)
res.add(matrix[i][j]);
//从上往下的每一列数据
for (int k = i + 1; k < row - i; k++)
res.add(matrix[k][collor - 1 - i]);
//判断是否会重复打印(从右向左的每行数据)
for (int m = collor - i - 2; (m >= i) && (row - i - 1 != i); m--)
res.add(matrix[row - i - 1][m]);
//判断是否会重复打印(从下往上的每一列数据)
for (int n = row - i - 2; (n > i) && (collor - i - 1 != i); n--)
res.add(matrix[n][i]);
}
return res;
}
public static void main(String[] args) {
int[][] arr={{1,2,3,4},{5,6,7,8},{9,10,11,12},{13,14,15,16}};
ArrayList<Integer> res= new Solution19().printMatrix(arr);
for (int i:res) {
System.out.printf("%d ",i);
}
}
}