Program to find word whose occurrence is maximum times in a sentence using Map STL

#include <string>
#include <iostream>
#include <map>
#include <utility>
using namespace std;

int main()
{
  map<string,int> ana;
string d,s[100],s1[100];
int i=0,j=0;
while(cin>>s[i])
{
s1[j++]=s[i++];
}

for( i=0;i<j;i++)
{
ana[s1[i]]++ ;
}

map<string,int>::iterator ii;
int max=ana.begin()->second;
d=ana.begin()->first;
for(ii =ana.begin(); ii!=ana.end(); ++ii)
{
  if(ii->second >max)
  {
  max=ii->second;
  d=ii->first;
  }
}

cout<<"\n Word '"<<d<<"' Occurs max times("<<max <<")";
    return 0;
}

Anagram using Map STL in C++

#include <string>
#include <iostream>
#include <map>
using namespace std;
int main()
{
  map<char,int> ana;
    map<char,int> ana1;
string s,s1;
int i,f=0;
cin>>s>>s1;

  for(i=0;i<s.length();i++)
  {
  ana[s[i]]++; //indexing each character of input string using map1
  }
 
  for(i=0;i<s1.length();i++)
  {
  ana1[s1[i]]++;   //indexing each character of input string using map2
  }
 
map<char,int>::iterator ii;  //iterator to access each element of map
map<char,int>::iterator jj;
if(ana.size()==ana1.size())
{
    for(ii =ana.begin(),jj=ana1.begin(); ii!=ana.end(); ++ii,++jj)
    {
      if(ii->first==jj->first&&ii->second==jj->second)
      {
      f=1;
      }
      else
      {
      f=0;
      break;
    }
    }

    if(f==0)
    cout<<"NOT";
    else
    cout<<"YEs";
}
else
cout<<"NOT";
return 0;
}

Program to Reverse a Sentence.

#include<iostream>
using namespace std;
string rev;
void reverse(string ch[],int n)
{
int i,j;
for(i=0,j=n-1;i<n/2;i++,j--)
{
string t=ch[i];
ch[i]=ch[j];
ch[j]=t;
}
for(i=0;i<n;i++)
{
cout<<ch[i]<<"  ";
}
}

int main()
{
string str[100],s[100];
int i=0,j=0;
while(cin>>str[i])
  {
  s[j]+=str[i++];
  j++;
  }
  reverse(s,j);
}

Efficient Program for Factorial using Memoization

#include <iostream>

using namespace std;

long long int cache[100000]={0};

long long int fact(long long int n)

{

if(n<=1)

return 1;

else 
    if(cache[n]>0)

return cache[n];

else

{

        long long int v=n*fact(n-1);

cache[n]=v;

return v;

}

}

int main()

 {

    long long int n;

   cin>>n;

   cout<<"Factorial of  "<<n <<"is = "<<fact(n);

   return 0;

}