void one_particle(int *grid, int n)
{
    /*//dynamically allocate memory for 3d array
    int* A = (int*)malloc(M*N*O*sizeof(int));
    for(int i = 0; i<M; i++)
        for(int j = 0; j<N; j++)for(int k=0; k<O;k++)
            *(A+i*N*O + j*O + k)=0;
    //print array
    for(int i = 0; i < M; i++){
        for(int j = 0; j<N; j++){
            for(int k = 0; k<O; k++)
                printf("%d", *(A + i*N*O + j*O + k));
            printf("\n");}
        printf("\n");
        }}*/
    int x=n,y=n,z=n;
    for(int i=1; i<=n; i++){
        int move = rand() % 6;
        if (move==0)
            x+=1;
        if (move==1)
            x-=1;
        if (move==2)
            y+=1;
        if (move==3)
            y-=1;
        if (move==4)
            z+=1;
        if (move==5)
            z-=1;}
        grid[((x * (2*n + 1) * (2* n + 1)) + (y * (2* n + 1)) +z)] += 1;
        printf("%ls", grid);
}

double squarert(int x) //square root bby
{
    double temp, number;
    if (x == 1)
        return (double) x;
    number = x/2;
    temp = 0;
    while (number!=temp){
        temp = number;
        number = (x/temp + temp) / 2;
    }
    return number;
}

//TODO
//Implement the following function
//This function returns the fraction of particles that lie within the distance
//r*n from the origin (including particles exactly r*n away)
//The distance used here is Euclidean distance
//Note: you will not have access to math.h when submitting on Mimir
double density(int *grid, int n, double r)
{
    double tot = 0;
    int index;
    int particles = 0;
    for (int i = 0; i < ((2*n +1) * (2*n+1) * (2*n+1)); i++){
        double distance = squarert(grid[i]);
        if (distance <= ((r*r)*(n*n)))
            tot += grid[i];
        particles += grid[i];}
 /*   for (int x = 0; x < (2*n + 1); x++){
        for (int y = 0; y < (2 * n + 1); y++){
            for (int z = 0; z < (2*n + 1); z++){
                index = ((x * (2*n + 1) * (2* n + 1)) + (y * (2* n + 1)) + z);
                printf("%d\n", index);
                if (squarert(x*x + y*y + z*z) <= (r*n)){

    //printf("x = %d,y = %d,z = %d\n", x,y,z);
                    tot += grid[index];}}}}
        printf("%f\n", tot);

    return (double)tot / ((2 * n + 1)*(2*n + 1)*(2*n + 1));*/
    return tot/particles;

}

//use this function to print results
void print_result(int *grid, int n)
{
    printf("radius density\n");
    for(int k = 1; k <= 20; k++)
    {
        printf("%.2lf   %lf\n", 0.05*k, density(grid, n, 0.05*k));
    }
}

//TODO
//Finish the following function
//See the assignment decription on Piazza for more details
void diffusion(int n, int m)
{
	//fill in a few line of code below
	int *grid=calloc((2*n+1)*(2*n+1)*(2*n+1), sizeof(int));
	for(int i = 1; i<=m; i++) one_particle(grid, n);
    //int *grid=calloc((2*n+1)*(2*n+1)*(2*n+1), sizeof(int));
	print_result(grid, n);
	//fill in some code below
    free(grid);

}