You are given a sorted unique integer array nums.

A range [a,b] is the set of all integers from a to b (inclusive).

Return the smallest sorted list of ranges that cover all the numbers in the array exactly. That is, each element of nums is covered by exactly one of the ranges, and there is no integer x such that x is in one of the ranges but not in nums.

Each range [a,b] in the list should be output as:

• "a->b" if a != b
• "a" if a == b

Example

Input: nums = [0,1,2,4,5,7]
Output: ["0->2","4->5","7"]
Explanation: The ranges are:
[0,2] --> "0->2"
[4,5] --> "4->5"
[7,7] --> "7"

Solution

/**
 * @param {number[]} nums
 * @return {string[]}
 */
var summaryRanges = function (nums) {
  for (let i = 0; i < nums.length; i++) {
    let j = i;
    // find the end of the range
    while (nums[j] + 1 === nums[j + 1]) j++;
    // if the range is more than one number, replace the range with the start and end
    if (j > i) {
      nums[i] = nums[i] + "->" + nums[j];
      nums.splice(i + 1, j - i);
    }
    // if the range is one number, just convert it to a string
    if (j === i) nums[i] = nums[i] + "";
  }
  return nums;
};