public static double lagrangeInterpolation(double[] xs, double[] ys, double x ){
double t;
double y = 0.0;

for(int k = 0; k< xs.length; k++){
t = 1.0;
for(int j = 0; j < xs.length ; j++){
if(j != k ){
t=t*((x-xs[j])/(xs[k]-xs[j]));
}
}
y += t*ys[k];
}
return y;