codeforce round A. Binary Protocol

A. Binary Protocol
time limit per test1 second
memory limit per test256 megabytes
inputstandard input
outputstandard output
Polycarp has just invented a new binary protocol for data transmission. He is encoding positive integer decimal number to binary string using following algorithm:

Each digit is represented with number of ‘1’ characters equal to the value of that digit (for 0 it is zero ones).
Digits are written one by one in order corresponding to number and separated by single ‘0’ character.
Though Polycarp learnt how to encode the numbers, he has no idea how to decode them back. Help him calculate the decoded number.

Input
The first line contains one integer number n (1 ≤ n ≤ 89) — length of the string s.

The second line contains string s — sequence of ‘0’ and ‘1’ characters, number in its encoded format. It is guaranteed that the number corresponding to the string is positive and doesn’t exceed 109. The string always starts with ‘1’.

Output
Print the decoded number.

Examples
input
3
111
output
3
input
9
110011101
output
2031
time limit per test1 second
memory limit per test256 megabytes
inputstandard input
outputstandard output
Polycarp has just invented a new binary protocol for data transmission. He is encoding positive integer decimal number to binary string using following algorithm:

Each digit is represented with number of ‘1’ characters equal to the value of that digit (for 0 it is zero ones).
Digits are written one by one in order corresponding to number and separated by single ‘0’ character.
Though Polycarp learnt how to encode the numbers, he has no idea how to decode them back. Help him calculate the decoded number.

Input
The first line contains one integer number n (1 ≤ n ≤ 89) — length of the string s.

The second line contains string s — sequence of ‘0’ and ‘1’ characters, number in its encoded format. It is guaranteed that the number corresponding to the string is positive and doesn’t exceed 109. The string always starts with ‘1’.

Output
Print the decoded number.

Examples
input
3
111
output
3
input
9
110011101
output
2031

模拟就好,可以再简洁一点,你们自己去改吧

#include <stdio.h>  
#include <stdlib.h>  
#include <string>  
#include <iostream>  
#include <algorithm>  
using namespace std;
long long a[100005], l[100005], r[100005];
int main()
{
    int n;
    string s,s2;
    while (cin >> n)
    {
        getchar();
        cin >> s;
        s2.clear();
        int  n0 = 0;
        int f = 1;
        if (s[s.size() - 1] != 0)
        {
            f = 0;
            s += '0';
        }
    //  cout << s << endl;
        if (f)
        {
            int n1 = 0, n0 = 0;
            for (int i = 0; i < s.size(); i++)
            {
                //cout << s[i] << endl;
                if (s[i] == '1')
                {
                    n1++;
                    n0 = 0;
                }
                if (s[i] == '0')
                {
                    n0++;
                    if(n1!=0)
                    cout << n1;
                    n1 = 0;
                    //cout << "n0=  " << n0 << endl;
                    if (n0 >1)
                        cout << "0";
                }
            }
        }
        else
        {
            int n1 = 0, n0 = 0;
            for (int i = 0; i < s.size(); i++)
            {
                //cout << s[i] << endl;
                if (s[i] == '1')
                {
                    n1++;
                    n0 = 0;
                }
                if (s[i] == '0')
                {
                    n0++;
                    //puts("shuzi")
                    if(n1!=0)
                    cout << n1;
                if (i == s.size())
                    break;
                    n1 = 0;
                    //puts("");
                //  cout << "n0=  " << n0 << endl;
                    if (n0 > 1)
                        cout << "0";

                }
            }
        }
        puts("");

    }
    return 0;
}