Contains Duplicate II

 1 struct Rec
 2 {
 3     int dig, ind;
 4 };
 5 bool cmp(struct Rec a,struct Rec b)
 6 {
 7     if(a.dig!=b.dig)
 8         return a.dig<b.dig;
 9     return a.ind<b.ind;
10 }
11 class Solution {
12 public:
13     bool containsNearbyDuplicate(vector<int>& nums, int k) {
14         int len=nums.size(),i;
15         struct Rec rec[len];
16         for(i=0;i<len;i++)
17         {
18             rec[i].dig=nums[i];
19             rec[i].ind=i;
20         }
21         sort(rec,rec+len,cmp);
22         for(i=0;i<len-1;i++)
23         {
24             if(rec[i].dig==rec[i+1].dig&&rec[i+1].ind-rec[i].ind<=k)
25                 return 1;
26         }
27         return 0;
28     }
29 };