_1232.java

packagecom.fishercoder.solutions.secondthousand;

publicclass_1232 {
publicstaticclassSolution1 {
/*
 * To check if they share the same slope, we use this formula:
 * <p>
 * check whether (y4 - y3)/(x4- x3) equals to (y2 - y1)/(x2 - x1)
 * considering denominator could be zero, we'll change it to use multiplication instead of division,
 * thus it becomes
 * check whether (y4 - y3)*(x2 - x1) equals (x4 - x3)*(y2 - y1)
 */
publicbooleancheckStraightLine(int[][] coordinates) {
for (inti = 2; i < coordinates.length - 1; i++) {
if ((coordinates[1][0] - coordinates[0][0])
 * (coordinates[i + 1][1] - coordinates[i][1])
 != (coordinates[1][1] - coordinates[0][1])
 * (coordinates[i + 1][0] - coordinates[i][0])) {
returnfalse;
 }
 }
returntrue;
 }
 }
}