HDU 3183 A Magic Lamp

直接模拟   如果后一位比前一位小，那就一直 向前 pop（）掉 维护他单调递增；

 #include<iostream>
 #include<cstring>
 #include<algorithm>
 #include<cmath>
 #include<stdio.h>
 #include<vector>
 using namespace std;

 char str[]; int res[],num;
 int main( )
 {
     while( scanf("%s%d",&str,&num) != EOF )
     {
         int len = strlen( str ); int k = ;
         for( int i = ; i < len; i++ )
         if( k !=  && num !=  && (str[i] - '') < res[k] )
         {
             while( k !=  && num !=  && (str[i] - '') < res[k] ){
                  k--; num--;
             }
               res[++k] = ( str[i] - '' );
         }else res[++k] = ( str[i] - '' );
          while( num-- && k !=  )k--;
          bool fell = false; bool fall = false;
         for( int i = ; i <= k; i++ )
         if(  res[i] ==   ){ if( fell )cout<<res[i]; }
         else { fell = true; cout<<res[i]; }
         if( !fell ) cout<<;puts("");
     }
     return ;
 }