1232. Check If It Is a Straight Line

//https://leetcode.com/problems/check-if-it-is-a-straight-line/
class Solution {
public:
    bool checkStraightLine(vector<vector<int>>& coordinates) {
        int dx = abs(coordinates[0][0]-coordinates[1][0]),
        dy = abs(coordinates[0][1]-coordinates[1][1]);
        
        for(int i = 1; i< coordinates.size()-1;i++){
            if(abs(coordinates[i][1]-coordinates[i-1][1]) * dx != abs(coordinates[i][0]-coordinates[i-1][0]) * dy)
                return false;
        }
        return true;
    }
};