hdu 3183 A Magic Lamp_hduprn-优快云博客

hdu 3183 A Magic Lamp

A Magic Lamp

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 3070 Accepted Submission(s): 1204

Problem Description
Kiki likes traveling. One day she finds a magic lamp, unfortunately the genie in the lamp is not so kind. Kiki must answer a question, and then the genie will realize one of her dreams.
The question is: give you an integer, you are allowed to delete exactly m digits. The left digits will form a new integer. You should make it minimum.
You are not allowed to change the order of the digits. Now can you help Kiki to realize her dream?

Input
There are several test cases.
Each test case will contain an integer you are given (which may at most contains 1000 digits.) and the integer m (if the integer contains n digits, m will not bigger then n). The given integer will not contain leading zero.

Output
For each case, output the minimum result you can get in one line.
If the result contains leading zero, ignore it.

Sample Input
178543 4
1000001 1
100001 2
12345 2
54321 2

Sample Output
13
1
0
123
321

题目大意：给你一串数字，让你删除其中m个数字后组成的数字最小，不能改变位置；

思路：设置数字的长度等于l，就是找l-m个数字组成的数字最小；
我们找l-m个数字，肯定是从头开始找，并且找最小的那个。

#include<bits/stdc++.h>
using namespace std;
int main()
{
    string s;
    int n;
    while(cin>>s>>n)
    {
        int l=s.size();
        int j=0;
        string ans;
        for(int i=1;i<=(l-n);i++)//取l-n个数 
        {
            int p=j; //重新设置位置；
            char minn=s[j];//重新设置最小的数；
            for( ;j<(n+i);j++)//从第j个开始取最小的数 
            {
                if(minn>s[j])
                {
                    minn=s[j];                  
                    p=j;
                }   
            }
            j=p+1;//重新设置下一个位置；
            if(minn=='0'&&ans=="");
            else
                ans+=minn;//把找到的最小的数给ans； 
        }
        if(ans=="")
            cout<<"0\n";
        else
            cout<<ans<<endl;
    }
    return 0;
}