【Array】54. Spiral Matrix

最新推荐文章于 2020-06-05 16:18:52 发布

原创最新推荐文章于 2020-06-05 16:18:52 发布 · 88 阅读

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本文介绍了一种螺旋遍历二维矩阵的方法，通过定义上下左右边界并逐步调整来避免越界，实现了从外向内逐层遍历矩阵的功能。

找规律 : 定位好left,right,up,bottom四个边界，防止越界

class Solution {
public:
    vector<int> spiralOrder(vector<vector<int>>& matrix) {
        
        vector<int> res;
        if(matrix.size()<1)
            return res;
        	int bot = matrix.size()-1, right = matrix[0].size()-1;
	int left = 0, up = 0;
	while (left<=right&&up<=bot&&right>=0&&bot>=0)
	{
		for (int i = left; i<=right; i++)
			res.push_back(matrix[up][i]);
		up++;   //print from the left to the right

		for (int i = up; i<=bot; i++)
			res.push_back(matrix[i][right]);
		right--;  //print from the up to the bottom

		for (int i =right; i >= left&&(up-1)!=bot; i--)
			res.push_back(matrix[bot][i]);
		bot--;  //print from the right to the left

		for (int i = bot; i >= up&&left!=(right+1); i--)
			res.push_back(matrix[i][left]);
		left++; //print from the bottom to the up
	}
        
        return res;
        
    }
};