I am trying to solve a coding problem where I am to check and see if a vector has unique values and if it does then return true else false.
So Far I thought of using a nested loops where you would compare the first to the last, but I am wanted to know if C++ has anything else then doing a o(n^2) type iteration. I saw that c++ has a unique function, but that would delete the unique value.
Example 1:
Input: nums = [1,2,3,1] Output: true Example 2:
Input: nums = [1,2,3,4] Output: false
std::unique checks for consecutive duplicates and moves them to the end of the range. It does not remove them from the vector. Anyhow you can make a copy. It also returns an iterator to the end of the range of unique values (that are now in the front of the vector):
#include <iostream>
#include <vector>
#include <algorithm>
bool only_unique(std::vector<int> v) {
std::sort(v.begin(),v.end());
return std::unique(v.begin(),v.end()) == v.end();
}
int main(){
std::cout << only_unique({1,2,3,1});
std::cout << only_unique({1,2,3,4});
}
If you don't want to use the additional memory you can change the argument to a reference. Currently, only_unique leaves the parameter unmodified. This has O(n log n) complexity.