Updated

Author: codewithdev

07-Algorithm STL/01-Iterator/Pair.cpp

@@ -0,0 +1,11 @@
+#include<iostream>
+#include<utility>
+using namespace std;
+int main()
+{
+	pair<int,int>p(10,20), p1(30,40);
+	cout<<(p==p1)<<endl;
+	cout<<(p!=p1)<<endl;
+	cout<<(p>p1)<<endl;
+	cout<<(p<p1)<<endl;
+}

07-Algorithm STL/01-Iterator/basic_of_iterator.cpp

@@ -0,0 +1,17 @@
+#include<iostream>
+#include<vector>
+using namespace std;
+
+int main(){
+	vector<int>v= {10,20,30,40,50,60};
+
+	vector<int>::iterator i= v.begin();    // Use this signature if you want to traverse only the single element.
+	cout<<(*i)<<endl;                     // Iterator are treated like Pointer.
+    i= next(i,2);
+    cout<<(*i)<<endl;
+    i= prev(i);
+    cout<<(*i)<<endl;
+
+
+    
+}

07-Algorithm STL/01-Iterator/classTemplate.cpp

@@ -0,0 +1,22 @@
+#include<iostream>
+using namespace std;
+template <typename T>
+struct pair{
+	T x,y;
+	pair(T i, T j){
+		x=i;
+		y=j;
+	}
+	T getFirst(){
+		return x;
+	}
+	T getSecond(){
+		return y;
+	}
+};
+int main()
+{
+	pair<int>p1(10,20);
+	cout<<p1.getFirst();
+	cout<p1.getSecond();
+}

07-Algorithm STL/binary_search.cpp

@@ -0,0 +1,20 @@
+#include<iostream>
+#include<algorithm>
+using namespace std;
+int main()
+{
+	int n;cin>>n;
+	int a[1000];
+	for(int i=0;i<n;i++){
+		cin>>a[i];
+	}
+   int key;cin>>key;
+   
+   bool present= binary_search(a, a+n, key);
+   if(present){
+   	cout<<"Present"<<endl;
+   }
+   else{
+   	cout<<"Not Present"<<endl;
+   }
+}

07-Algorithm STL/find.cpp

@@ -0,0 +1,18 @@
+#include<iostream>
+#include<algorithm>
+using namespace std;
+int main()
+{
+    int arr[]= {10,20,30,14,155};
+    int n= sizeof(arr)/sizeof(int);
+    int key;
+    cin>>key;
+    auto it= find(arr,arr+n,key);
+    int index= it-arr;
+    if(key==n){
+        cout<<"Key not found"<<endl;
+    }
+    else{
+    cout<<index<<endl;
+}
+}

07-Algorithm STL/indian_money.cpp

@@ -0,0 +1,18 @@
+#include<iostream>
+#include<algorithm>
+using namespace std;
+bool compare(int a, int b){
+    return a<=b;
+}
+int main()
+{
+    int coins[]={1,2,5,10,20,50,100,200,500,2000};
+    int money;cin>>money;
+    int n= sizeof(coins)/sizeof(int);
+    while(money>0){
+        int lb= lower_bound(coins, coins+n, money,compare)-coins-1;
+        int m= coins[lb];
+        cout<<m<<",";
+        money= money-m;
+    }
+}

07-Algorithm STL/lower_bound.cpp

@@ -0,0 +1,15 @@
+#include<iostream>
+#include<algorithm>
+using namespace std;
+int main(){
+	int n;cin>>n;
+	int a[1000];
+	for(int i=0;i<n;i++){
+		cin>>a[i];
+	}
+	int key;cin>>key;
+
+	auto it= lower_bound(a,a+n, key);
+	int index= it-a;
+	cout<<"Lower Bound of "<<key<<"is: "<<index<<endl;
+}

07-Algorithm STL/pair.cpp

@@ -0,0 +1,24 @@
+#include<iostream>
+#include<algorithm>
+using namespace std;
+int main()
+{
+    pair<int,string> p= make_pair(100,"Audi");
+    cout<<p.first<<endl;
+    cout<<p.second<<endl;
+
+//second way;
+
+pair<int,string>p2;
+p2.first= 200;
+p2.second="Buggatti";
+cout<<p2.first<<" "<<p2.second<<endl;
+
+//Taking input;
+
+int n;cin>>n;
+string s;
+getline(cin,s);
+pair<int, string> p3= make_pair(n,s);
+cout<<p3.first<< "," <<p3.second<<endl;
+}

07-Algorithm STL/rotate.cpp

@@ -0,0 +1,18 @@
+#include<iostream>
+#include<algorithm>
+#include<vector>
+using namespace std;
+int main(){
+    int a[]= {10,20,30,40,50,60,70};
+    int n= sizeof(a)/sizeof(int);
+    rotate(a,a+3,a+n);
+    for(int i=0;i<n;i++){
+        cout<<a[i]<<" ";
+    }
+    cout<<endl;
+    vector <int> v{10,20,30,40,50,60};
+    rotate(v.begin(), v.begin()+3, v.end());
+    for(int i=0;i<v.size();i++){
+        cout<<v[i]<<" ";
+    }
+}

07-Algorithm STL/upper_bound.cpp

@@ -0,0 +1,20 @@
+#include<iostream>
+#include<algorithm>
+using namespace std;
+int main()
+{
+    int n;cin>>n;
+    int a[1000];
+    for(int i=0;i<n;i++){
+    	cin>>a[i];
+
+    }
+    int key;cin>>key;
+    auto it= lower_bound(a,a+n,key);
+    int lb= it-a;
+    auto it2= upper_bound(a,a+n,key);
+    int ub= it-a;
+
+    cout<<"Occurrence of "<<key<<"is :"<<(ub-lb)<<endl;
+
+}

08-Vector/insert.cpp

@@ -0,0 +1,11 @@
+#include<iostream>
+#include<vector>
+using namespace std;
+int main()
+{
+	vector<int>v{1,2,3,4,5,14};
+	v.insert(v.begin()+3, 3, 100);
+	for(int x:v){
+		cout<<x<<",";
+	}
+}

08-Vector/pop_back.cpp

@@ -0,0 +1,11 @@
+#include<iostream>
+#include<vector>
+using namespace std;
+int main()
+{
+	vector<int>v{1,2,3,4,5,6,19};
+	v.pop_back();
+	for(int x:v){
+		cout<<x<<",";
+	}
+}

08-Vector/push_back.cpp

@@ -0,0 +1,11 @@
+#include<iostream>
+#include<vector>
+using namespace std;
+int main()
+{
+	vector<int>v{1,2,3,4,5,6};
+	v.push_back(10);
+	for(int x:v){
+		cout<<x<<",";
+	}
+}

08-Vector/vector_pair.cpp

@@ -0,0 +1,19 @@
+#include<iostream>
+#include<vector>
+#include<algorithm>
+bool compare()
+using namespace std;
+int main()
+{
+	int n;cin>>n;
+	vector<pair<int,int>>v;
+	for(int i=0;i<n;i++){
+		int x,y;
+		cin>>x>>y;
+		v.push_back(make_pair(x,y));
+	}
+	sort(v.begin(),v.end());
+	for(auto p:v){
+		cout<<p.first<<","<<p.second<<endl;
+	}
+}

09- Number Theory/PrimeSeive.cpp

@@ -0,0 +1,32 @@
+#include<iostream>
+using namespace std;
+#define ll long long
+void primeSieve(int *p){
+	for(int i=3;i<=1000000;i+=2){
+		p[i]=1;
+	}
+	//Sieve
+
+	for(ll i=3;i<=1000000;i+=2){
+		if(p[i]==1){
+			for(ll j=i*i;j<=1000000;j++){
+				p[j]=0;
+			}
+		}
+	}
+	//special Case
+	p[2]=1;
+	p[1]=p[0]=0;
+}
+int main()
+{
+	int n;cin>>n;
+	int p[100005]= {0};
+	primeSieve(p);
+	for(int i=0;i<=n;i++){
+		if(p[i]==1){
+			cout<<i<<" ";
+		}
+	}
+	return 0;
+}

09- Number Theory/SieveProblem.cpp

@@ -0,0 +1,35 @@
+#include<iostream>
+using namespace std;
+#define ll long long
+void primesieve(int *p){
+ for(int i=3;i<=1000000;i+=2){
+		p[i]=1;
+	}
+	//Sieve
+
+	for(ll i=3;i<=1000000;i+=2){
+		if(p[i]==1){
+			for(ll j=i*i;j<=1000000;j++){
+				p[j]=0;
+			}
+		}
+	}
+	//special Case
+	p[2]=1;
+	p[1]=p[0]=0;
+}
+
+int main()
+{
+	int p[1000005]={0};
+	int csum[100000]={0};
+	primesieve(p);
+	int q;cin>>q;
+	for(int i=1;i<=1000000;i++){
+		csum[i]= csum[i-1]+p[i];
+	}
+	while(q--){
+		int a,b;cin>>a>>b;
+		cout<<csum[b]-csum[a-1]<<endl;
+	}
+}

09- Number Theory/gcd.cpp

@@ -0,0 +1,10 @@
+#include<iostream>
+using namespace std;
+int gcdofnumber(int a, int b){
+	return b==0?a:gcdofnumber(b,a%b);
+}
+int main()
+{
+	int a,b;cin>>a>>b;
+	cout<<gcdofnumber(a,b);
+}

09- Number Theory/lcm.cpp

@@ -0,0 +1,20 @@
+#include<iostream>
+using namespace std;
+int gcdofnumbers(int a, int b){
+	return b==0?a:gcdofnumbers(b,a%b);
+}
+int lcmofnumbers(int a,int b){
+	int lcm=0;
+	int product= 0;
+	if(a>0 and b>0){
+		product+= a*b;
+        lcm= product/gcdofnumbers(a,b);
+	}
+	return lcm;
+
+}
+int main()
+{
+	int a,b;cin>>a>>b;
+	cout<<lcmofnumbers(a,b);
+}

10- Recursion & Backtracking/LinearSearch.cpp

@@ -0,0 +1,18 @@
+#include<iostream>
+using namespace std;
+int linearSearch(int *a, int i, int key, int n){
+	if(i==n){
+		return -1;
+	}
+	if(i==key){
+		return i;
+	}
+	return linearSearch(a, i+1, key,n);
+}
+int main()
+{
+	int a[]= {1,2,3,5,4,8};
+	int n= sizeof(a)/sizeof(int);
+	int key;cin>>key;
+	cout<<linearSearch(a,0,key,n);
+}