leetcode 498. Diagonal Traverse 矩阵对角遍历 + 控制方向即可

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;
}
};