C++ notes

Binery_search.cpp

@@ -0,0 +1,51 @@
+
+
+                   //Binery Search
+
+#include <bits/stdc++.h>
+using namespace std;
+
+int findIndex(int a[], int n, int target)
+{
+  int low=0, mid, high=n-1;
+
+  while(low<=high){
+    mid=(low+high)/2;
+
+    if(a[mid]==target){
+      return mid;
+    }
+    else if(a[low]<=a[mid]){
+        if(target<=a[mid] && target >= a[low]){
+            high=mid-1;
+        }else{
+            low=mid+1;
+        }
+    }
+    else{
+      if(target>=a[mid] && target<=a[high]){
+         low=mid+1;
+      }else{
+        high=mid-1;
+      }
+    }
+  }
+  return -1;
+}
+
+int main(){
+  int n;
+  cin>>n;
+
+  int a[n];
+  for (int i = 0; i < n; i++){
+     cin>>a[i];
+  }
+
+  int target;
+  cin>>target;
+
+  cout<<findIndex(a,n,target);
+
+  return 0;
+}

Kandane's_algorithum.cpp

@@ -0,0 +1,35 @@
+
+                //Kandane's algorithum
+
+// #include <bits/stdc++.h>
+// using namespace std;
+
+// int main(){
+//   int n;
+//   cin>>n;
+
+//   int a[n];
+
+//   for(int i=0; i<n; i++){
+//     cin>>a[i];
+//   }
+
+//   int max_sum = INT_MIN, current_sum=0;
+
+//   for(int i=0; i<n; i++){
+
+//     current_sum = current_sum+a[i];
+
+//     if(current_sum > max_sum){
+//       max_sum = current_sum;
+//     }
+//     if(current_sum < 0){
+//       current_sum = 0;
+//     }
+
+//   }
+
+//   cout<<max_sum<<endl;
+
+//   return 0;
+// }

cyclicshift.cpp

@@ -0,0 +1,19 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int main(){
+    int arr[]={1,2,3,4,5,6,7,8,9};
+    int n=9;
+    int k=4;
+
+    reverse(arr, arr+n-k);
+    reverse(arr+n-k, arr+n);
+    reverse(arr, arr+n);
+
+    for(int i=0; i<n; i++){
+        cout<<arr[i]<<" ";
+    }
+    cout<<"\n";
+
+    return 0;
+}

function1.cpp

@@ -0,0 +1,67 @@
+#include <iostream>
+using namespace std;
+
+//function declaration 
+void party (string);
+
+//function definition
+void party(string n){
+    cout<<"hey "<<n<<", welcome to our party\n";
+    cout<<"yeyy.. its fun\n";
+}
+int main(){
+    string x="adi";
+    party(x);
+
+    return 0;
+}
+
+
+
+// #include <iostream>
+// using namespace std;
+
+// //function declaration 
+// void multiply5(int&);
+
+// //function definition
+// void multiply5(int& a){
+//     a=a*5;
+// }
+
+// int main(){
+//     int x=10;
+//     //function calling
+//     multiply5(x);
+//     cout<<x<<"\n";
+//     return 0;
+// }
+
+
+
+//all lower}else if(){ letters to upper }else if(){
+
+
+
+// #include <iostream>
+// using namespace std;
+
+// //function definition
+// string  stringConvert(string s){
+//      string res=s;
+//      for(int i=0; i<s.length(); i++){
+//          if(s[i]-'A'>=0 && s[i]-'A'<= 25){  //big to small
+//             res[i]=res[i]-'A'+'a';
+//          }else if(s[i]-'a'>=0 && s[i]-'a'<= 25){  //small to big
+//             res[i]=res[i]-'a'+'A';
+//          }
+//      }
+//      return res;
+// }
+
+// int main(){
+//     string s="adithya&*&DSNFKJHDKSFKDSFKD";
+//     string res1=stringConvert(s);
+//     cout<<res1<<"\n";
+//     return 0;
+// }

pointers.cpp

@@ -0,0 +1,38 @@
+#include <iostream>
+using namespace std;
+
+int main(){
+    int a=25;
+    int *p=&a;
+    cout<<a<<" "<<p<<" "<<&a<<" "<<*p<<"\n";
+    return 0;
+}
+
+
+          //& adress print in void 
+
+#include <iostream>
+using namespace std;
+
+int main(){
+    char a=63;
+    void* p=&a;
+
+    cout<<p<<"\n";
+
+    return 0;
+}
+
+       //* value print in void 
+
+#include <iostream>
+using namespace std;
+
+int main(){
+    char a=63;
+    void* p=&a;
+
+    cout<<*(char*)p<<"\n";
+
+    return 0;
+}

sets.cpp

@@ -0,0 +1,25 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int main(){
+    set<int> s;
+
+    s.insert(4);
+    s.insert(3);
+    s.insert(1);
+    s.insert(2);
+
+    for(int element:s){
+        cout<<element<<"\n";
+    }
+
+    cout<<"\n";
+
+    s.erase(3);
+
+    for(int element:s){
+        cout<<element<<"\n";
+    }
+
+    return 0;
+}

unordered_map.cpp

@@ -0,0 +1,39 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int main(){
+  int n; //length of the array
+  cin>>n;
+
+  int a[n]; //an array of length n
+
+  for(int i=0; i<n; i++){
+    cin>>a[i];
+  }
+
+  unordered_map<int,int> mp;
+
+  int sum = 0, find_sub=0;
+
+  for(int i=0;i<n;i++){
+    sum = sum+a[i];
+
+    if(sum==0){
+      find_sub = 1;
+    }
+    else{
+        if(mp[sum]>0){
+          find_sub = 1;
+        }else{
+          mp[sum]++;
+        }
+    }
+  }
+  if(find_sub == 1){
+    cout<<"True"<<endl;
+  }else{
+    cout<<"False"<<endl;
+  }
+
+  return 0;
+}