leetcode-1711.js

/**
 * @param {number[]} deliciousness
 * @return {number}
 */
var countPairs = function(deliciousness) {
  let max = deliciousness[0]
  for (let i=1; i < deliciousness.length; i++) {
    if (deliciousness[i] > max) {
      max = deliciousness[i]
    }
  }

  const memo = {}
  let i=0
  for (let j=0; i < max*2; j++) {
    i=2**j
    memo[i] = true
  }
  
  let count = 0
  for (let i=0; i < deliciousness.length - 1; i++) {
    for (let j=i+1; j < deliciousness.length; j++) {
      const sum = deliciousness[i] + deliciousness[j]
      if (memo[sum]) {
        count++
      }
    }
  }
  return count
};