bestMeetingPoint.cpp

/*
Description
A group of two or more people wants to meet and minimize the total travel distance. You are given a 2D grid of values 0 or 1, where each 1 marks the home of someone in the group. The distance is calculated using Manhattan Distance, where distance(p1, p2) = |p2.x - p1.x| + |p2.y - p1.y|.

Example
Example 1:

Input:
[[1,0,0,0,1],[0,0,0,0,0],[0,0,1,0,0]]
Output:
6

Explanation:
The point `(0,2)` is an ideal meeting point, as the total travel distance of `2 + 2 + 2 = 6` is minimal. So return `6`.
Example 2:

Input:
[[1,1,0,0,1],[1,0,1,0,0],[0,0,1,0,1]]
Output:
14
*/

class Solution {
public:
    /**
     * @param grid: a 2D grid
     * @return: the minimize travel distance
     */
    int minTotalDistance(vector<vector<int>> &grid) {
        // Write your code here
        vector<pair<int, int>>points;
        for (int i = 0; i < grid.size(); i++) {
            for (int j = 0; j < grid[i].size(); j++) {
                if (grid[i][j]) points.push_back({i,j});
            }
        }
        int sum, ans = INT_MAX;
        for (int i = 0; i < grid.size(); i++) {
            for (int j = 0; j < grid[i].size(); j++) {
                sum = 0;
                for (int k = 0; k < points.size(); k++) {
                    sum+=(abs(i-points[k].first)+abs(j-points[k].second));
                }
                ans = min(ans, sum);
            }
        }
        return ans;
    }
};
/**
 * Definition for a point.
 * struct Point {
 *     int x;
 *     int y;
 *     Point() : x(0), y(0) {}
 *     Point(int a, int b) : x(a), y(b) {}
 * };
 */
class Solution {
public:
    /**
     * @param points an array of point
     * @return an integer
     */
    int maxPoints(vector<Point>& points) {
        // Write your code here
        unordered_map<float,int> mp;
		int maxNum = 0;
		for(int i = 0; i < points.size(); i++)
		{
			mp.clear();
			mp[INT_MIN] = 0;
			int duplicate = 1;
			for(int j = 0; j < points.size(); j++)
			{
				if(j == i) continue;
				if(points[i].x == points[j].x && points[i].y == points[j].y)
				{
					duplicate++;
					continue;
				}
				float k = points[i].x == points[j].x ? INT_MAX : (float)(points[j].y - points[i].y)/(points[j].x - points[i].x);
				mp[k]++;
			}
			unordered_map<float, int>::iterator it = mp.begin();
			for(; it != mp.end(); it++)
				if(it->second + duplicate > maxNum)
					maxNum = it->second + duplicate;
		}
		return maxNum;
    }
};