Leetcode 498. 对角线遍历 [硬模拟]

画个图找一下规律，简单模拟一下就出来了。

class Solution {
    public:
        vector findDiagonalOrder(vector>& mat) {
            vector vec;
            int i, j;
            i = j = 0;
            bool flag = true;
            while(flag) {
                while(flag) {
                    if(i >= mat.size() || j >= mat[0].size()) {flag = false; break;}
                    vec.push_back(mat[i][j]);
                    i -= 1; j += 1;
                    if(j >= mat[0].size()) {
                        j -= 1;
                        i += 2;
                        flag = false;
                        break;
                    } else if(i < 0) {
                        i += 1;
                        flag = false;
                        break;
                    }
                }
                while(!flag) {
                    if(i >= mat.size() || j >= mat[0].size()) {flag = false; break;}
                    vec.push_back(mat[i][j]);
                    j -= 1; i += 1;
                    if(i >= mat.size()) {
                        i -= 1;
                        j += 2;
                        flag = true;
                        break;
                    } else if(j < 0) {
                        j += 1;
                        flag = true;
                        break;
                    }
                }
            }
            return vec;
        }
};