leetcode 498. Diagonal Traverse 矩阵对角遍历

Given a matrix of M x N elements (M rows, N columns), return all elements of the matrix in diagonal order as shown in the below image.

Example:
Input:
[
[ 1, 2, 3 ],
[ 4, 5, 6 ],
[ 7, 8, 9 ]
]
Output: [1,2,4,7,5,3,6,8,9]
Explanation:

Note:
The total number of elements of the given matrix will not exceed 10,000.

本题题意很简单，就是对矩阵做一个对角遍历，其实可以遍历所有的对角，然后依次插入即可

代码如下：

#include <iostream>#include <vector>#include <map>#include <set>#include <queue>#include <stack>#include <string>#include <climits>#include <algorithm>#include <sstream>#include <functional>#include <bitset>#include <cmath>using namespace std;class Solution {public:    vector<int> findDiagonalOrder(vector<vector<int>>& mat)    {        vector<int> res;        if (mat.size() <= 0)            return res;        int row = mat.size(), col = mat[0].size();        for (int i = 0; i < row + col - 1; i++)        {            int x, y;            if (i <= row - 1)            {                x = i;                y = 0;            }            else            {                x = row - 1;                y = i - row + 1;            }            vector<int> one;            while (x >= 0 && y < col)                one.push_back(mat[x--][y++]);            if (i % 2 == 0)            {                for (int j = 0; j<one.size(); j++)                    res.push_back(one[j]);            }            else            {                for (int j = one.size() - 1; j >= 0; j--)                    res.push_back(one[j]);            }        }        return res;    }};