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Intersection of Two Arrays in C++
Suppose we have two arrays; we have to find their intersections.
So, if the input is like [1,5,3,6,9],[2,8,9,6,7], then the output will be [9,6]
To solve this, we will follow these steps −
Define two maps mp1, mp2
Define an array res
for x in nums1
(increase mp1[x] by 1)
for x in nums2
(increase mp2[x] by 1)
for each key-value pair x in mp1
cnt := 0
cnt := minimum of value of x and mp2[key of x]
if cnt > 0, then −
insert key of x at the end of res
return res
Example
Let us see the following implementation to get a better understanding −
#include <bits/stdc++.h>
using namespace std;
void print_vector(vector<auto> v){
cout << "[";
for(int i = 0; i<v.size(); i++){
cout << v[i] << ", ";
}
cout << "]"<<endl;
}
class Solution {
public:
vector<int> intersection(vector<int>& nums1, vector<int>& nums2){
unordered_map<int, int> mp1, mp2;
vector<int> res;
for (auto x : nums1)
mp1[x]++;
for (auto x : nums2)
mp2[x]++;
for (auto x : mp1) {
int cnt = 0;
cnt = min(x.second, mp2[x.first]);
if (cnt > 0)
res.push_back(x.first);
}
return res;
}
};
main(){
Solution ob;
vector<int> v = {1,5,3,6,9}, v1 = {2,8,9,6,7};
print_vector(ob.intersection(v, v1));
}Input
{1,5,3,6,9},{2,8,9,6,7}Output
[9, 6, ]
Updated on: 10-Jun-2020
1K+ Views
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