void removeDuplicate(char *str){//using set
set<char> m;//set will contain only unique elements
char temp[1];
for(int i=0;i<strlen(str);i++)
m.insert(str[i]);
set<char>::iterator i;
int j=0;
for(i=m.begin();i!=m.end();i++){
str[j++]=*i;
}
str[j]=”;
}
This programs removes dulplicate elements in a string without using an additional array
//Time complexity O(n^2)
#include<iostream>
#include<string.h>
#include<algorithm>
#include<stdlib.h>
using namespace std;
void removeDuplicate(char* str){
if(str==”)
return;
int pivot=1;
int len=strlen(str);
//i runs from 2nd element to last element because j runs from first element to pivot
//element and we need not compare same elements so i and j neve have same value at same time
for(int i=1;i<len;i++){
int j;
//make all elements before the pivot as unique
for(j=0;j<pivot;j++)
if(str[j]==str[i])
break;
if(j==pivot){
//if j==pivot (str to str+pivot) is a unique subarray where str[pivot]=str[i]
str[pivot]=str[i];
pivot++;
}
}
str[pivot]=”;
}
int main(){
char str[]=”asddfffafffafffafaffafaf”;
removeDuplicate(str);
cout<<str;
}
coding hangover 