bzoj1150

haha，貪心，邊界條件折騰了我一會兒
 1 #include<cstdio>
 2 #include<cctype>
 3 #include<queue>
 4 #include<algorithm>
 5 using namespace std ;
 6 
 7 const int MAXN = 1000000 + 200 ;
 8 int N , K ;
 9 int dis [ MAXN ] ;
10 int l [ MAXN ] ;
11 int r [ MAXN ] ;
12 int v [ MAXN ] ;
13 int vis [ MAXN ] ;
14 int ans ;
15 struct cmp {
16     bool operator () ( const int a , const int b ) { return v [ a ] > v [ b ] ; } ;
17 } ;
18 priority_queue < int , vector < int > , cmp > q ;
19 
20 int main () {
21     scanf ( "%d%d" , & N , & K ) ;
22     for ( int i = 1 ; i <= N ; ++ i ) scanf ( "%d" , dis + i ) ;
23     for ( int i = 1 ; i < N ; ++ i ) v [ i ] = dis [ i + 1 ] - dis [ i ] ;
24     for ( int i = 1 ; i < N - 1 ; ++ i ) r [ i ] = i + 1 ;
25     for ( int i = 2 ; i < N ; ++ i ) l [ i ] = i - 1 ;
26     for ( int i = 1 ; i < N ; ++ i ) q . push ( i ) ;
27     fill_n ( vis + 1 , N , 1 ) ;
28     v [ 0 ] = 1000000000 + 1 ;
29     v [ N ] = 1000000000 + 1;
30     while ( K -- ) {
31         while ( ! vis [ q . top () ] ) q . pop () ;
32         const int o = q . top () ; q . pop () ;
33         ans += v [ o ] ;
34         vis [ l [ o ] ] = 0 ;
35         vis [ r [ o ] ] = 0 ;
36         v [ o ] = v [ l [ o ] ] + v [ r [ o ] ] - v [ o ] ;
37         q . push ( o ) ;
38         l [ o ] = l [ l [ o ] ] ; r [ o ] = r [ r [ o ] ] ;
39         r [ l [ o ] ] = l [ r [ o ] ] = o ;
40     }
41     printf ( "%d\n" , ans ) ;
42 }