1329. 将矩阵按对角线排序

class Solution {
public:
    vector<vector<int>> diagonalSort(vector<vector<int>>& mat) {
        int n = mat.size(), m = mat[0].size();
        unordered_map<int, vector<int>> vs;
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < m; ++j)
                vs[i - j].emplace_back(mat[i][j]);
        }
        for (auto& v : vs) sort(v.second.rbegin(), v.second.rend());

        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < m; ++j) {
                mat[i][j] = vs[i - j].back();
                vs[i - j].pop_back();
            }
        }
        return mat;
    }
};

class Solution {
public:
    vector<vector<int>> diagonalSort(vector<vector<int>>& mat) {
        if(mat.empty()) return mat;
        for(int i = 0; i < mat.size(); i++){
            vector<int> tmp;
            getValue(mat, tmp, i, 0);
            sort(tmp.begin(), tmp.end());
            setValue(mat, tmp, i, 0);
        }

        for(int j = 1; j < mat[0].size(); j++) {
            vector<int> tmp;
            getValue(mat, tmp, 0, j);
            sort(tmp.begin(), tmp.end());
            setValue(mat, tmp, 0, j);
        }
        return mat;
    }

    void getValue(vector<vector<int>>& m, vector<int>& value, int i, int j){
        int rows = m.size(), cols = m[0].size();
        while(i < rows && j < cols){
            value.push_back(m[i++][j++]);
        }
    }

    void setValue(vector<vector<int>>& m, vector<int>& value, int i, int j){
        int rows = m.size(), cols = m[0].size();
        int k = 0;
        while(i < rows && j < cols){
            m[i++][j++] = value[k++];
        }
    }
};