Topcoder SRM 598 div2 A

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

         

            Problem Statement          

       

          Fox Ciel received a string as a birthday present. However, the           string was too long for her, so she decided to make it shorter by           erasing some characters.
The erasing process will look as           follows:
         

           
1.               Find the smallest i such that the i-th character and the               (i+1)-th character of the string are same.            
           
2.               If there is no such i, end the process.            
           
3.               Remove the i-th and the (i+1)-th character of the string, and               repeat from 1.            
         

         
         
          For example, if she receives "cieeilll", she will change the string           as follows: "cieeilll" -> "ciilll" -> "clll" -> "cl". You are given           a string s. Return the string she will get after she erases           characters as described above.        

         

            Definition          

       

                                                                                                                                                                                                                                                                                                                             

Class:	ErasingCharacters
Method:	simulate
Parameters:	string
Returns:	string
Method signature:	string simulate(string s)
(be sure your method is public)

       

         

            Constraints          

       

          -        

          s will contain between 1 and 50 characters, inclusive.        

          -        

          Each character in s will be a lowercase letter ('a'-'z').        

         

            Examples          

       

          0)        

                                                                                                                                     

                                                                                       

                     

"cieeilll"

                   

             

               

Returns: "cl"

             

                                                                                       

                      This is the example from the statement.                    

             

       

          1)        

                                                                                                                                     

                                                                                       

                     

"topcoder"

                   

             

               

Returns: "topcoder"

             

                                                                                       

                      She won't erase any characters at all.                    

             

       

          2)        

                                                                                                                                     

                                                                                       

                     

"abcdefghijklmnopqrstuvwxyyxwvutsrqponmlkjihgfedcba"

                   

             

               

Returns: ""

             

       

          3)        

                                                                                                                                     

                                                                                       

                     

"bacaabaccbaaccabbcabbacabcbba"

                   

             

               

Returns: "bacbaca"

             

       

          4)        

                                                                                                                                     

                                                                                       

                     

"eel"

                   

             

               

Returns: "l"

             

       

   

      This problem statement is the exclusive and proprietary property of       TopCoder, Inc. Any unauthorized use or reproduction of this information       without the prior written consent of TopCoder, Inc. is strictly       prohibited. (c)2003, TopCoder, Inc. All rights reserved.    

#include <cstdio>
#include <iostream>
#include <vector>
#include <set>
#include <cstring>
#include <string>
#include <map>
#include <cmath>
#include <stack>
#include <ctime>
#include <algorithm>
#include <queue>

using namespace std;
#define INF 0x7fffffff
#define maxm 1001
#define mod 1000000007
#define mp make_pair
#define pb push_back
#define rep(i,n) for(int i = 0; i < (n); i++)
#define re return
#define fi first
#define se second
#define sz(x) ((int) (x).size())
#define all(x) (x).begin(), (x).end()
#define sqr(x) ((x) * (x))
#define sqrt(x) sqrt(abs(x))
#define y0 y3487465
#define y1 y8687969
#define fill(x,y) memset(x,y,sizeof(x))

typedef vector<int> vi;
typedef long long ll;
typedef long double ld;
typedef double D;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<string> vs;
typedef vector<vi> vvi;

template<class T> T abs(T x) { re x > 0 ? x : -x; }
const int maxn = 1015;
int n, m, t, k, x, l, r, s, sk,y,top,temp;
class ErasingCharacters{
public:
    string simulate(string s){
        for (int i = 0; i < s.length();i++)
        if (s[i] == s[i + 1])s.erase(s.begin() + i, s.begin() + i + 2), i -= 2;
        return s;
    }
};