[leetcode]498. Diagonal Traverse

Analysis

完了完了 真的要找不到工作了！！！！！蒼了天了！！！—— [每天刷題並不難0.0]

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.

注意一下方向的變化以及順序就行了

Implement

class Solution {
public:
    vector<
 
int> findDiagonalOrder(vector<vector<int>>& matrix) {
        vector<int> res;
        int m = matrix.size();
        if(m == 0)
            return res;
        int n = matrix[0].size();
        int r = 0;
        int c = 0;
        int d = 0;
        int dir[2][2] = {{-1, 1}, {1
 
, -1}};
        int cnt = 0;
        while(cnt < m*n){
            res.push_back(matrix[r][c]);
            r += dir[d][0];
            c += dir[d][1];
            if(r >= m){
                r = m-1;
                c += 2;
                d = 1-d;
            }
            if(c >= n){
                c =
 
 n-1;
                r += 2;
                d = 1-d;
            }
            if(r < 0){
                r = 0;
                d = 1-d;
            }
            if(c < 0){
                c = 0;
                d = 1-d;
            }
            cnt++;
        }
        return res;
        
    }
    
};