【剑指Offer】顺时针打印矩阵

2020-09-23 10:58:39 浏览数 (1)

题目

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。

示例 1:

输入:matrix = [[1,2,3],[4,5,6],[7,8,9]] 输出:[1,2,3,6,9,8,7,4,5] 示例 2:

输入:matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]] 输出:[1,2,3,4,8,12,11,10,9,5,6,7]

限制:

0 <= matrix.length <= 100 0 <= matrix[i].length <= 100

题解

代码语言:javascript复制
class Solution {
    public int[] spiralOrder(int[][] matrix) {
        if(matrix.length == 0) return new int[0];
        int l = 0, r = matrix[0].length - 1, t = 0, b = matrix.length - 1, x = 0;
        int[] res = new int[(r   1) * (b   1)];
        while(true) {
            for(int i = l; i <= r; i  ) res[x  ] = matrix[t][i]; // left to right.
            if(  t > b) break;
            for(int i = t; i <= b; i  ) res[x  ] = matrix[i][r]; // top to bottom.
            if(l > --r) break;
            for(int i = r; i >= l; i--) res[x  ] = matrix[b][i]; // right to left.
            if(t > --b) break;
            for(int i = b; i >= t; i--) res[x  ] = matrix[i][l]; // bottom to top.
            if(  l > r) break;
        }
        return res;
    }
}

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