# Puzzle #529

Today we need to look for some numbers and sum it up. So what is the problem? We have numbers without signs, but also some with minuses and pluses both before number and after it. So we need to make some conditional assumptions. Check it out.

## Loading libraries and data

`library(tidyverse)`

library(readxl)

path = "Excel/529 Sum with Signs.xlsx"

input = read_excel(path, range = "A1:A10")

test = read_excel(path, range = "B1:B10")

## Transformation

`pattern <- "(?<=\\D)[+-]?\\d+[+-]?"`

result = input %>%

mutate(numbers = str_extract_all(Strings, pattern)) %>%

mutate(adj_num = map_dbl(numbers,

~sum(as.numeric(str_replace_all(.x, "[+-]", "")) *

ifelse(str_detect(.x, "-"), -1, 1)), na.rm = TRUE))

## Validation

`identical(result$adj_num, test$`Answer Expected`)`

#> [1] TRUE

# Puzzle #530

Money again… We need to summarise amount earned by each person, but emphasize only days and amounts that was maximal per person. So lets do some fast pivoting and summarizing.

## Loading libraries and data

`library(tidyverse)`

library(readxl)

path = "Excel/530 Dates for Max Sales.xlsx"

input = read_excel(path, range = "A2:I11")

test = read_excel(path, range = "J2:K11")

## Transformation

`result <- input %>%`

pivot_longer(cols = -Name, names_to = c(".value", ".type"), names_pattern = "(Date|Amount)(.*)") %>%

fill(Date, .direction = "down") %>%

fill(Amount, .direction = "up") %>%

select(-c(2)) %>%

distinct() %>%

group_by(Name) %>%

filter(Amount == max(Amount)) %>%

summarise(Date = paste(Date, collapse = ", "), Amount = first(Amount)) %>%

ungroup()

# Puzzle #531

Number mixing in progress. We need to find first 500 numbers that have following properties. They can not be divisible by 10, it have to be divisible by number created by removing one digit from number. We also have to list those dividers. It is very hard calculation to do and very time consuming process. I don’t like if my code is running slow, so I tried to optimize it. And that’s why I post here both solutions.

## Loading libraries and data

`library(charcuterie)`

library(tidyverse)

library(readxl)

path = "Excel/531 Numbers Divisible after Removing a Digit.xlsx"

test = read_excel(path, range = "A2:B502")

## Transformation v1 — slow

`transform_number <- function(number) {`

num_str <- as.character(number)

num_split <- chars(num_str)

len <- length(num_split)

result <- character(len)

for (i in seq_along(num_split)) {

result[i] <- paste0(num_split[-i], collapse = "")

}

result <- paste(result, collapse = ", ")

return(result)

}

transform_number <- Vectorize(transform_number)

numbers <- data.frame(number = 101:1000000) %>%

filter(number %% 10 != 0)

n1 = numbers %>%

mutate(new_number = map_chr(number, transform_number)) %>%

separate_rows(new_number, sep = ", ") %>%

distinct() %>%

mutate(new_number = as.numeric(new_number)) %>%

filter(number %% new_number == 0, new_number != 1) %>%

summarise(divisors = paste(new_number, collapse = ", "), .by = "number") %>%

head(500)

## Transformation v2 — faster

`find_divisors = function(n) {`

digits = strsplit(as.character(n), NULL)[[1]]

divisors = integer(0)

for (i in seq_along(digits)) {

reduced_number = as.integer(paste0(digits[-i], collapse = ""))

if (reduced_number > 1 && n %% reduced_number == 0) {

divisors = c(divisors, reduced_number)

}

}

return(divisors)

}

find_numbers = function(count = 500, start = 101) {

result = list()

number = start

while (length(result) < count) {

if (number %% 10 != 0) {

divisors = find_divisors(number)

if (length(divisors) > 0) {

result[[as.character(number)]] = divisors

}

}

number = number + 1

}

return(result)

}

numbers_with_divisors = find_numbers()

numbers_with_divisors = map(numbers_with_divisors, unique)

df = tibble(

Number = names(numbers_with_divisors) %>% as.numeric(),

Divisors = I(unname(numbers_with_divisors))

) %>%

mutate(Divisors = map_chr(Divisors, ~ paste(.x, collapse = ", ")))

## Validation

`all.equal(n1, test, check.attributes = FALSE) `

#> [1] TRUE

identical(df, test) # TRUE

# Puzzle #532

If you think cummulating numbers what do you see in your mind? Sometimes I think about Ebenezer Scrooge stacking coins. And numbers provided in table looks alike as well. We have matrix that starts with one number: 1 in left top corner, and we need to step further always writing down sum of all available at this moment surrounding numbers. And they are cummulates very fast. Let’s do it.

## Loading libraries and data

`library(tidyverse)`

library(readxl)

path = "Excel/532 Grid where each is sum of already filled in surrounding cells.xlsx"

test = read_excel(path, range = "B2:K11", col_names = FALSE) %>% as.matrix()

## Transformation

`matrix_size <- 10`

m <- matrix(0, nrow = matrix_size, ncol = matrix_size)

m[1, 1] <- 1

for (i in 1:matrix_size) {

for (j in 1:matrix_size) {

if (i != 1 || j != 1) {

m[i, j] <- sum(m[pmax(i - 1, 1):pmin(i + 1, matrix_size),

pmax(j - 1, 1):pmin(j + 1, matrix_size)])

}

}

}

## Validation

`all.equal(m, test, check.attributes = FALSE) # TRUE`

# Puzzle #533

And again we are drawing, this time some stars. We are suppose to draw eight-arm star with odd number of length of arm. And as you already guessed, if we need to make some graphic, I will probably use matrix. And you are right.

## Loading libraries and data

`library(tidyverse)`

library(readxl)

path = "Excel/533 ASCII Star.xlsx"

test5 = read_excel(path, range = "F3:J7", col_names = FALSE)

test7 = read_excel(path, range = "E9:K15", col_names = FALSE)

test9 = read_excel(path, range = "D17:L25", col_names = FALSE)

test11 = read_excel(path, range = "C27:M37", col_names = FALSE)

## Transformation

`draw_ascii_star = function(number) {`

matrix = matrix(NA, nrow = number, ncol = number)

for (i in 1:number) {

matrix[i, number %/% 2 + 1] = "*"

matrix[number %/% 2 + 1, i] = "*"

matrix[i, i] = "*"

matrix[i, number - i + 1] = "*"

}

result = as.data.frame(matrix)

colnames(result) = NULL

rownames(result) = NULL

return(result)

}

## Validation

`a5 = draw_ascii_star(5)`

all.equal(a5, test5, check.attributes = FALSE) # TRUE

a7 = draw_ascii_star(7)

all.equal(a7, test7, check.attributes = FALSE) # TRUE

a9 = draw_ascii_star(9)

all.equal(a9, test9, check.attributes = FALSE) # TRUE

a11 = draw_ascii_star(11)

all.equal(a11, test11, check.attributes = FALSE) # TRUE

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On my Github repo there are also solutions for the same puzzles in Python. Check it out!