Leetcode刷題54. 螺旋矩陣
阿新 • • 發佈:2020-12-10
技術標籤:陣列、連結串列、跳錶陣列
給定一個包含m x n個元素的矩陣(m 行, n 列),請按照順時針螺旋順序,返回矩陣中的所有元素。
示例1:
輸入:
[
[ 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:
[
[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]
來源:力扣(LeetCode)
連結:https://leetcode-cn.com/problems/spiral-matrix
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class Solution { //定義4個變數,分別從矩陣的上下左右進行遍歷 //時間複雜度O(m*n),空間複雜度O(1) public List<Integer> spiralOrder(int[][] matrix) { List<Integer> result = new ArrayList<>(); if (matrix == null || matrix.length == 0 || matrix[0].length == 0) return result; //定義變數 int left = 0, right = matrix[0].length - 1, top = 0, bottom = matrix.length - 1; while (left <= right && top <= bottom) { //從左到右 for (int col = left; col <= right; col++) { result.add(matrix[top][col]); } top++; //從上到下 for (int row = top; row <= bottom; row++) { result.add(matrix[row][right]); } right--; //從右到左 if (top <= bottom) { for (int col = right; col >= left; col--) { result.add(matrix[bottom][col]); } } bottom--; //從下到上 if (left <= right) { for (int row = bottom; row >= top; row--) { result.add(matrix[row][left]); } } left++; } return result; } }