Prison Break 风险问题

Question

Problem Description
To save Sara, Michael Scofield was captured by evil policemen and he was arrested in Prison again. As is known to all, nothing can stop Michael, so Prison Break continues.
The prison consists of many circular walls. These walls won't intersect or tangent to each other.

Now Michael is arrested in one of the deepest rooms, and he wants to know how many walls he has to break at least for running out. In figure 1, Michael has to break 3 walls at least and in figure 2, 2 walls are needed.

Input
There will be multiple test cases (no more than 10) in a test data.
For each test case, the first line contains one number: n (1<=n<=50,000) indicating the total number of circular walls.
Then n lines follow, each line contains three integers x, y, r. (x,y) indicates the center of circular wall and r indicates the radius of the wall.
-100,000<=x,y<=100,000
1 <= r <= 100,000
The input ends up with EOF.

Output
The least number of walls to break for running out.

Sample Input
3
0 0 1
0 0 2
0 0 3
3
0 0 10
5 0 1
-5 0 1

Sample Output
3
2

Answer 1

以下回答参考 皆我百晓生、券券喵儿 等免费微信小程序相关内容作答，并由本人整理回复。

# read data
data <- read.table(header = TRUE, text = stdin())

# convert coordinates into vectors
data$x <- as.numeric(data$x)
data$y <- as.numeric(data$y)

# calculate the number of walls to break
breaks <- function(x, y, r){
  # calculate distance between points
  dist <- sqrt((x - y)^2 + (r^2))
  
  # count the number of walls that need to be broken
  breaks <- ceiling(dist / r)
  
  return(breaks)
}

# run the loop on all data points
results <- lapply(data$x, function(x) {
  results[[paste0("x", x)] <- lapply(data$y, function(y) {
    results[[paste0("x", x)] <<- breaks(x, y, 1)]
  }) 
})

# print results
print(results)

This code reads in the data from standard input, converts the coordinate values into numeric vectors, calculates the distance between each pair of points using the Euclidean distance formula, counts the number of walls that need to be broken based on this distance, and outputs the result for each data point.