[LeetCode] Spiral Matrix

最新推荐文章于 2019-07-07 11:13:21 发布

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本文介绍了一种遍历矩阵元素的螺旋顺序算法，并通过示例代码演示了如何实现矩阵中元素的螺旋遍历。

Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.

For example,
Given the following matrix:

[
 [ 1, 2, 3 ],
 [ 4, 5, 6 ],
 [ 7, 8, 9 ]
]

You should return [1,2,3,6,9,8,7,4,5].

class Solution {
public:
    vector<int> spiralOrder(vector<vector<int> > &matrix) {
        vector<int> result;
        if(matrix.size() == 0)
            return result;
        int x1 = 0,y1 = 0,x2 = matrix.size() - 1,y2 = matrix[0].size() - 1;
        while(x1 <= x2 && y1 <= y2){
            for(int i = y1;i <= y2;i ++) result.push_back(matrix[x1][i]);
            for(int i = x1 + 1;i <= x2;i ++) result.push_back(matrix[i][y2]);
            if(x1 != x2)
                for(int i = y2 - 1;i >= y1;i --) result.push_back(matrix[x2][i]);
            if(y1 != y2)
                for(int i = x2 - 1;i > x1;i --) result.push_back(matrix[i][y1]);
            x1 ++;x2 --;y1 ++;y2 --;
        }
        return result;
    }
};