golf-results-2020-summer

Task

Rules

The program performs a simulation of an epidemic simulation and prints ASCII's map of people (see examples).
The output must be printed to STDOUT.
The output must have a newline char (\n) at the end.
Program gets 2 arguments (argv)
Arguments are always valid.
First argument K is an integer defining the number of iterations.
Second argument is a string representing the population separated with commas (see description of the XYSQ code below).
Each line must have newline char (\n) at the end.
The last line must not have any characters after newline char (\n).

Description

Inspiration for this golf is another simulation created by Washington Post (https://www.washingtonpost.com/graphics/2020/world/corona-simulator/).

The goal of this golf is to create a simulation of a virus spreading across the population.

$ ./task 10 22H0,33S0
........
........
........
.S......
....S...
........
........
........

The area is always 8x8 size.

Each person is described with the XYSQ code, where:

X - position in X axis, from 0 to 7;
Y - position in Y axis, from 0 to 7;
S - State of the person, we have 3 states:
- H - Healthy person, can be infected;
- S - Sick person, can infect healthy person and after 14 iterations changes to R state;
- R - Recovered person, cannot be infected;
Q - Quarantine state, 0 or 1, if Q is 1< then the person can't move;
Additionaly, the person has a hidden N value - it's a grain for random moving (please see step flow). Initial value is n = (x << 2)^7 * (y << 3)^5 where:
- << is a bit shift
- ^ is a XOR operation

Step flow

function next_iteration(P) {
    for (person in P) { // iterate in a sequence
        person.s = cure(person.s)
        person.n = gen_n(person.n)
        [new_x, new_y] = gen_new_cords(person)
        if (point {new_x, new_y} is free and person.q == 0) { 
            person.x = new_x
            person.y = new_y
        }
        if (person.s == H and in the neightbourhood (use Moore) is a sick individual) {
            // https://en.wikipedia.org/wiki/Moore_neighborhood
            person.s = S
        }
    }
}

function cure(state) {
    if (state == S and 14 iterations has passed since the individual got sick) {
        return R
    } else {
        return state
    }
}

function gen_n(n) {
    n ^= n << 13
    n ^= n >> 17
    n ^= n << 5
    return n % (1 << 30)
}

function gen_new_cords(person) {
    x = person.x
    y = person.y
    switch(person.n modulo 4) {
        case 0: x += 1
        case 1: x -= 1
        case 2: y += 1
        case 3: y -= 1
    }
    // wrap points, like in pacman game
    if (x >= WIDTH)  x -= WIDTH  else if (x < 0) x += WIDTH
    if (y >= HEIGHT) y -= HEIGHT else if (y < 0) y += HEIGHT
    return [x, y]
}

Examples

$ ./task 1 25H0,32S0,46R1,63H1,76S1
........
........
........
...S..H.
........
...H....
....R..S
........

$ ./task 2 25H0,32S0,46R1,63H1,76S1
........
........
........
....S.H.
...S....
........
....R..S
........

$ ./task 14 25H0,32S0,46R1,63H1,76S1
.R......
........
........
......S.
.......S
........
....R..R
........