leetcode--1232 缀点成线

问题描述：

示例1

输入：coordinates = [[1,2],[2,3],[3,4],[4,5],[5,6],[6,7]]
输出：true

示例2

输入：coordinates = [[1,1],[2,2],[3,4],[4,5],[5,6],[7,7]]
输出：false

java代码

class Solution {
    public boolean checkStraightLine(int[][] coordinates) {
        if(coordinates.length==1||coordinates.length==2){
            return true;
        }
        boolean flag=true;
        for(int i=1;i<coordinates.length-1;i++){
            for(int j=0;j<coordinates[i].length;j++){
                double x1=coordinates[i-1][0],y1=coordinates[i-1][1];
                double x2=coordinates[i][0],y2=coordinates[i][1];
                double x3=coordinates[i+1][0],y3=coordinates[i+1][1];
                if(x2-x1!=0&&x3-x2!=0){
                     if((y2-y1)/(x2-x1)!=(y3-y2)/(x3-x2)){
                     flag=false;
                     break;
                }
                }
            }
        }
        return flag;
    }
}