SOURCE

var isMonotonic = function(nums) {
    let max = true
    let min = true
if(nums[0] < nums[nums.length-1]) {
  for(let i =0; i <= nums.length-2; i++){
      if(nums[i+1] < nums[i]) {
          max = false
      }
  }
}else { 
  for(let j =0; j <= nums.length-2; j++){
      if(nums[j+1]>nums[j]) {
          min = false
      }
  }
}
return max && min
};
console.log('这是',isMonotonic([1,3,2]))