题目：

Given a sorted integer array where the range of elements are [0, 99] inclusive, return its
missing ranges.
For example, given [0, 1, 3, 50, 75], return [“2”, “4->49”, “51->74”, “76->99”]

 

解答：

 1 public class Solution {
 2 
 3     public static void main(String[] args) {
 4         int[] arr = {0,1,3,50,75};
 5         int start = 0;
 6         int end = 99;
 7         
 8         List<String> results = findMissingRanges(arr, start, end);
 9     }
10 
11     public List<String> findMissingRanges(int[] vals, int start, int end) {
12         List<String> ranges = new ArrayList<>();
13         int prev = start - 1;
14         for(int i = 0; i <= vals.length; i++) {
15             int curr = (i == vals.length)?end+1:vals[i];
16             if(curr - prev >= 2) {
17                 ranges.add(getRange(prev+1, curr-1));
18             }
19 
20             prev = curr;
21         }
22 
23         return ranges;
24     }
25 
26     private String getRange(int from, int to) {
27         return (from == to)?String.valueOf(from):from+"->" + to;
28     }
29 }