Euler 9

library(dplyr)
t <- expand.grid(a = 1:1000, b = 1:1000)


answer <- t %>% 
  mutate(sum = a + b) %>% 
  filter(sum < 1000) %>% 
  select(-sum) %>% 
  mutate(c = sqrt(a^2 + b^2)) %>% 
  mutate(sum = a + b + c) %>% 
  filter(sum == 1000) %>% 
  slice(1) %>% 
  transmute(answer = a*b*c)