Matrix Cells in Distance Order Solutions in C++

// Source : https://leetcode.com/problems/matrix-cells-in-distance-order/
// Author : Hao Chen
// Date   : 2019-04-21



class Solution {
public:
    void put(int R, int C, int r, int c, vector<vector<int>>& res) {
        if (r>=0 && r < R && c>=0 && c<C ) {
            res.push_back({r,c});
        }
    }
    vector<vector<int>> allCellsDistOrder(int R, int C, int r0, int c0) {
        int n =  R+C-2;
        vector<vector<int>> result;
        result.push_back({r0,c0});
        for(int i=1; i<= n; i++) {
            // from (r0-i, c0) to (r0, c0+i)
            for(int r=r0-i,c=c0;r!=r0; r++, c++)  put (R, C, r ,c, result);

            // from  (r0, c0+i) to (r0+i, c0)
            for(int r=r0, c=c0+i; c!=c0; r++, c-- ) put (R, C, r, c, result);

            // from (r0+i, c0) to (r0, c0-i)
            for (int r=r0+i, c=c0; r!=r0; r--, c--) put (R, C, r, c, result);

            // from (r0, c0-i) to (r0-i, c0)
            for (int r=r0, c=c0-i; c!=c0; r--, c++) put (R, C, r, c, result);
        }

        return result;
    }
};

/// Source : https://leetcode.com/problems/matrix-cells-in-distance-order/
/// Author : liuyubobobo
/// Time   : 2019-04-20

#include <iostream>
#include <vector>

using namespace std;


/// Greedy
/// Time Complexity: O(nlogn)
/// Space Complexity: O(n)
class Solution {
public:
    int twoCitySchedCost(vector<vector<int>>& costs) {

        vector<vector<int>> A, B;

        int res = 0;
        for(const vector<int>& cost: costs)
            if(cost[0] < cost[1])
                res += cost[0], A.push_back(cost);
            else
                res += cost[1], B.push_back(cost);

        vector<vector<int>>& t = A.size() < B.size() ? B : A;

        sort(t.begin(), t.end(), [](const vector<int>& v1, const vector<int>& v2){
           return abs(v1[0] - v1[1]) > abs(v2[0] - v2[1]);
        });

        while(t.size() > costs.size() / 2){
            res += abs(t.back()[0] - t.back()[1]);
            t.pop_back();
        }
        return res;
    }
};


int main() {

    return 0;
}