技術標籤：劍指offer串和陣列java演算法

原題連結

題目描述

輸入一個矩陣，按照從外向裡以順時針的順序依次打印出每一個數字。

示例 1

輸入：matrix = [[1,2,3],[4,5,6],[7,8,9]]
輸出：[1,2,3,6,9,8,7,4,5]

示例 2

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

限制

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

解法：邊框控制

這道題目太經典，期末實訓、藍橋杯、都遇見了，控制好邊界範圍就行

public int[] spiralOrder(int[][] matrix) {
    if(matrix == null || matrix.length == 0 || matrix[0].length == 0) return new int[0];
    int[] result = new int[matrix.length * matrix[0].length];
    int left = 0, right = matrix[0].length - 1, top = 0, bottom = matrix.length - 1, index = -1;
    while (left <=
 
 right && top <= bottom){
        // 上
        for (int i = left; i <= right; i++) {
            result[++index] = matrix[top][i];
        }
        // 右
        for (int i = top + 1; i <= bottom; i++) {
            result[++index] = matrix[i][right];
        }
        if(left < right &&
 
 top < bottom){
            // 下
            for (int i = right - 1; i >= left ; --i) {
                result[++index] = matrix[bottom][i];
            }
            //左
            for (int i = bottom - 1; i > top; --i) {
                result[++index] = matrix[i][left];
            }
        }
        ++left;
        --right;
        ++top;
        --bottom;
    }
    return result;
}

提交結果