Q3.js

let a = 1
let b = 1
let count = 0

while (a <= 20) {
  while (b <= 20) {
    if (((a * 2 + b) <= 20) && a * 2 > b && a !== b) {
      console.log(`發現等邊三角形 | 三邊長分別為: ${a}、${a}、${b}`)
      count++
    }
    b++
  }
  a++
  b = 1
}

console.log(`共找到 ${count} 組等腰三角形`)