[LeetCode]Spiral Matrix

题目

Number: 54
Difficulty: Medium
Tags: Array

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].

题解

螺旋数组问题。

常规方法就是分四条边考虑，注意各种边界。

代码

vector<int> spiralOrder(vector<vector<int>>& matrix) {    vector<int> res;    if(matrix.empty())        return res;    int m = matrix.size(), n = matrix[0].size();    int max = m * n, i = 0, j = 0, cur = 0, level = 0;    while(cur < max){        while(j < n - level && cur < max){            res.push_back(matrix[i][j]);            cur++;            j++;        }        j--;        i++;        while(i < m-level && cur < max){            res.push_back(matrix[i][j]);            cur++;            i++;        }        i--;        j--;        while(j >= level && cur < max){            res.push_back(matrix[i][j]);            cur++;            j--;        }        j++;        i--;        while(i > level && cur < max){            res.push_back(matrix[i][j]);            cur++;            i--;        }        i++;        j++;        level++;    }    return res;}