Day 7 of 30-Day LeetCode Challenge
1 min readApr 15, 2020
Given an integer array arr
, count element x
such that x + 1
is also in arr
.
If there’re duplicates in arr
, count them seperately.
class Solution {
public:
int countElements(vector<int>& arr) { //O(nlogn)
sort(arr.begin(), arr.end());
int result = 0;
for(int i=0;i<arr.size();){
int j = i+1;
while(j<arr.size()&&arr[i]==arr[j]){
++j;
}
if(j<arr.size()&&arr[i]+1==arr[j]) {
//cout<<i<<”, “<<j<<endl;
result += j-i;
}
i = j;
}
return result;
}
};