bzoj1150

haha，贪心，边界条件折腾了我一会儿
 #include<cstdio>
 #include<cctype>
 #include<queue>
 #include<algorithm>
 using namespace std ;

 const int MAXN =  +  ;
 int N , K ;
 int dis [ MAXN ] ;
 int l [ MAXN ] ;
 int r [ MAXN ] ;
 int v [ MAXN ] ;
 int vis [ MAXN ] ;
 int ans ;
 struct cmp {
     bool operator () ( const int a , const int b ) { return v [ a ] > v [ b ] ; } ;
 } ;
 priority_queue < int , vector < int > , cmp > q ;

 int main () {
     scanf ( "%d%d" , & N , & K ) ;
     for ( int i =  ; i <= N ; ++ i ) scanf ( "%d" , dis + i ) ;
     for ( int i =  ; i < N ; ++ i ) v [ i ] = dis [ i +  ] - dis [ i ] ;
     for ( int i =  ; i < N -  ; ++ i ) r [ i ] = i +  ;
     for ( int i =  ; i < N ; ++ i ) l [ i ] = i -  ;
     for ( int i =  ; i < N ; ++ i ) q . push ( i ) ;
     fill_n ( vis +  , N ,  ) ;
     v [  ] =  +  ;
     v [ N ] =  + ;
     while ( K -- ) {
         while ( ! vis [ q . top () ] ) q . pop () ;
         const int o = q . top () ; q . pop () ;
         ans += v [ o ] ;
         vis [ l [ o ] ] =  ;
         vis [ r [ o ] ] =  ;
         v [ o ] = v [ l [ o ] ] + v [ r [ o ] ] - v [ o ] ;
         q . push ( o ) ;
         l [ o ] = l [ l [ o ] ] ; r [ o ] = r [ r [ o ] ] ;
         r [ l [ o ] ] = l [ r [ o ] ] = o ;
     }
     printf ( "%d\n" , ans ) ;
 }