TZOJ 4493: Remove Digits

4493: Remove Digits

时间限制(普通/Java):1000MS/3000MS     内存限制:65536KByte
总提交:
329
          
测试通过:77

描述

Given an N-digit number, you should remove K digits and make the new integer as large as possible.

输入

The first line has two integers N and K (1 ≤ K<N≤500000).
The next line has a N-digit number with no leading zero.

输出

Output the largest possible integers by removing K digits.

样例输入

4 2
2835

样例输出

85

 #include <bits/stdc++.h>
 using namespace std;
 char s[];
 int main()
 {
     ios::sync_with_stdio(false);
     int n,k,num=;
     char c;
     s[]='';
     cin>>n>>k;
     for(int i=;i<n;i++){
         cin>>c;
        while(c>s[num]){
             if(!k||!num) break;
             num--,k--;
        }
         s[++num]=c;
    }
     if(k)
         num=num-k;
     s[++num]='\0';
     cout << s+ << endl;
     return ;
 }