最大连续递增数字串

题目：求最大连续递增数字串（如“ads3sl456789DF3456ld345AA”中的“456789”。

答：

#include "stdafx.h"
#include <iostream>
#include <string>

using namespace std;

//求最大连续递增数字串
string FindMaxIncreNumberSeq(string str)
{
    if ("" == str || str.length() <= 0)
    {
        return NULL;
    }
    int maxlength = 0;
    int start = -1;
    int count = 0;
    int pos = -1;
    bool isbegin = true;
    for (int i = 0; i < str.length(); i++)
    {
        if (str[i] >= '0' && str[i] <= '9')
        {
            if (isbegin)
            {
                pos = i;
                isbegin = false;
                count = 1;
            }
            else if (str[i] - str[i - 1] == 1)
            {
                count++;
            }
            else
            {
                if (maxlength < count)
                {
                    maxlength = count;
                    start = pos;
                }
                pos = i;
                count = 1;
            }

            if (maxlength < count)
            {
                maxlength = count;
                start = pos;
            }
        }
        else
        {
            if (maxlength < count)
            {
                maxlength = count;
                start = pos;
            }
            isbegin = true;
        }
    }
    return str.substr(start, maxlength);
}

int _tmain(int argc, _TCHAR* argv[])
{
    string str = "23456789ads3sl456789DF012341234567893456ld345AA345678";
    cout<<"字符串："<<str<<endl;
    cout<<"最大连续递增数字串：";
    cout<<FindMaxIncreNumberSeq(str);

    cout<<endl;
    return 0;
}

运行界面如下：