Check If It Is a Straight Line

Description

You are given an array coordinates, coordinates[i] = [x, y], where [x, y] represents the coordinate of a point. Check if these points make a straight line in the XY plane.

Example 1:

Input: coordinates = [[1,2],[2,3],[3,4],[4,5],[5,6],[6,7]]

Output: true

Example 2:

Input: coordinates = [[1,1],[2,2],[3,4],[4,5],[5,6],[7,7]]

Output: false

Constraints:

• 2 <= coordinates.length <= 1000

• coordinates[i].length == 2

• -10^4 <= coordinates[i][0], coordinates[i][1] <= 10^4

• coordinates contains no duplicate point.

code

class Solution {
    public boolean checkStraightLine(int[][] coordinates) {
        if (coordinates.length == 2) return true;
        int x = coordinates[1][0] - coordinates[0][0];
        int y = coordinates[1][1] - coordinates[0][1];
        for (int i = 2; i < coordinates.length; i++) {
            int tx = coordinates[i][0] - coordinates[0][0];
            int ty = coordinates[i][1] - coordinates[0][1];
            if (x * ty - tx * y != 0) return false;
        }
        return true;
    }
}