Solution of some code interview for the @acme company

solution.js

function solve(ip, arr) {
  let min = 0
  let max = ip
  arr.forEach(tuple => {
    const i = tuple[0] // 5
    const j = tuple[1]
    if (i > min) {
      const newMax = i - 1
      if (newMax < max){
        max = i - 1
      }
    }

    if (i <= min) {
      const newMin = j + 1
      if (newMin>min) {
        min = j + 1
      }
    }
  })
  if (min>ip) return -1
  return min
}

console.log(solve(8, [[0,0],[4,6],[2,3]]) === 1)
console.log(solve(8, [[5,6],[0,1],[2,3]]) === 4)
console.log(solve(8, [[5,6],[1,3],[7,7]]) === 0)
console.log(solve(8, [[5,6],[0,1],[1,3],[7,7]]) === 4)
console.log(solve(8, [[0,7],[0,7],[0,7],[0,7]]) === 8)
console.log(solve(8, [[0,8]]) === -1)
console.log(solve(8, [[0,3],[4,8]]) === -1)