1232. 缀点成线

class Solution {
public:
    bool checkStraightLine(vector<vector<int>>& coordinates) 
    {
        int x = coordinates[0][0], y = coordinates[0][1];
        int chax = coordinates[1][0] -x , chay = coordinates[1][1] - y;
        for(int i = 2;i<coordinates.size();i++)
        {
            if(chay * (coordinates[i][0] -x) !=  chax*(coordinates[i][1] - y)) 
                return false;
        }
        return 1;
    }
};