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Author: maityamit

012 - Hashmaps/001 Maximum Frequency Number.cpp

@@ -0,0 +1,17 @@
+#include <unordered_map>
+int highestFrequency(int arr[], int n) {
+ // Write your code here
+ int max=0,count=0;
+ unordered_map<int,int> seen;
+ for(int i=0;i<n;i++){
+ seen[arr[i]]++;
+ if(seen[arr[i]]>count){
+ count=seen[arr[i]];
+ }
+ }
+ for(int i=0;i<n;i++){
+ if(count==seen[arr[i]]){
+ return arr[i];
+ }
+ }
+}

012 - Hashmaps/002 Print Intersection.cpp

@@ -0,0 +1,14 @@
+#include <bits/stdc++.h>
+void printIntersection(int arr1[], int arr2[], int n, int m) {
+ // Write your code here
+ unordered_map<int,int> seen;
+ for(int i=0;i<n;i++){
+ seen[arr1[i]]++;
+ }
+ for(int i=0;i<m;i++){
+ if(seen.count(arr2[i])==1 && seen[arr2[i]]>0){
+ cout<<arr2[i]<<endl;
+ seen[arr2[i]]--;
+ }
+ }
+}

012 - Hashmaps/003 Pair Sum to 0.cpp

@@ -0,0 +1,29 @@
+#include <bits/stdc++.h>
+int pairSum(int *arr, int n) {
+// Write your code here
+ // unordered_map<int,int> seen;
+ // int count=0;
+ // for(int i=0;i<n;i++){
+ // seen[arr[i]]++;
+ // }
+ // unordered_map<int,int> :: iterator it = seen.begin();
+ // while(it!=seen.end()){
+ // int f = it->second;
+ // int s = seen[0-(it->first)];
+ // count+=(f*s);
+ // seen[0-(it->first)]=0;
+ // it++;
+ // }
+ // return count;
+ unordered_map<int, int>map;
+ int k=0;
+ int count=0;
+ for(int i=0;i<n;i++){
+ int a=k-arr[i];
+ if(map.count(a)==1){
+ count+=map[a];
+ }
+ map[arr[i]]++;
+ }
+ return count;
+}

012 - Hashmaps/004 Extract Unique characters.cpp

@@ -0,0 +1,15 @@
+#include<unordered_map>
+#include<string>
+string uniqueChar(string str) {
+// Write your code here
+ string st;
+ unordered_map<char,int> seen;
+ for(int i=0;i<str.length();i++){
+ if(seen.count(str[i])==0){
+ st+=str[i];
+ }
+ seen[str[i]]++;
+ }
+ return st;
+ 
+}

012 - Hashmaps/005 Longest Consecutive Sequence.cpp

@@ -0,0 +1,56 @@
+#include <bits/stdc++.h>
+vector<int> helper(int* arr,int n){
+ unordered_map<int,int> map;
+ for(int i=0;i<n;i++) map[arr[i]]++;
+ 
+ int start;
+ int end;
+ int max = INT_MIN;
+ for(int i=0;i<n;i++){
+ int count=0;
+ int temp = arr[i];
+ while(map.count(temp+1)==1){
+ count++;
+ temp++;
+ }
+ if(count>max){
+ start=arr[i];
+ end=temp;
+ max=count;
+ }
+ }
+ return {start,end};
+}
+vector<int> longestConsecutiveIncreasingSequence(int *arr, int n) {
+ 
+ 
+ return helper(arr,n);
+ 
+ 
+ 
+ // Your Code goes here
+ // unordered_map<int,int> seen;
+ // for(int i=0;i<n;i++){
+ // seen[arr[i]]++;
+ // }
+ // int max=INT_MIN;
+ // int count=0;
+ // int start,end;
+ // for(int i=0;i<n;i++){
+ // int temp = arr[i]+1;
+ // while(seen.count(temp)==1){
+ // count++;
+ // temp++;
+ // }
+ // if(count>max){
+ // start=arr[i];
+ // end=temp-1;
+ // max=count;
+ // }
+ // count=0; 
+ // }
+ // vector<int> vt;
+ // vt.push_back(start);
+ // vt.push_back(end);
+ // return vt;
+}

012 - Hashmaps/006 Pairs with difference K.cpp

@@ -0,0 +1,21 @@
+#include<unordered_map>
+#include<cmath>
+
+int getPairsWithDifferenceK(int *arr, int n, int k) {
+ 
+ 
+ unordered_map<int,int> seen;
+ int count=0;
+ for(int i=0;i<n;i++){
+ int a = arr[i]+k;
+ int b = arr[i]-k;
+ if(seen.count(a)>=1){
+ count+=seen[a];
+ }
+ else if(seen.count(b)>=1){
+ count+=seen[b];
+ }
+ seen[arr[i]]++;
+ }
+ return count;
+}

012 - Hashmaps/007 Longest subset zero sum.cpp

@@ -0,0 +1,25 @@
+#include <climits> 
+#include<unordered_map>
+int lengthOfLongestSubsetWithZeroSum(int* arr, int n) {
+ // Write your code here
+ int max = INT_MIN;
+ unordered_map<int,int> seen;
+ int sum=0;
+ for(int i=0;i<n;i++){
+ sum+=arr[i];
+ if(sum==0){
+ if((i+1)>max){
+ max=i+1;
+ }
+ }
+ if(seen.count(sum)>=1){
+ int temp = i-seen[sum];
+ if(temp>max){
+ max=temp;
+ }
+ }
+ seen[sum]=i; 
+ 
+ }
+ return max;
+}