bzoj 1045

确定初始状态（n与1直接谁给了谁几个），后面的就确定了，再根据总结出来的东西决定前面谁给谁几个最优。

n=1000000!!!

 /**************************************************************
     Problem: 1045
     User: idy002
     Language: C++
     Result: Accepted
     Time:1852 ms
     Memory:12524 kb
 ****************************************************************/

 #include <cstdio>
 #include <algorithm>
 #define maxn 1000010
 using namespace std;

 int n;
 int a[maxn];
 long long s[maxn], sum, mv;

 int main() {
     scanf( "%d", &n );
     for( int i=; i<=n; i++ ) {
         scanf( "%d", a+i );
         sum += a[i];
     }
     sum /= n;
     for( int i=; i<=n; i++ )
         a[i] -= sum;
     for( int i=; i<=n; i++ )
         s[i] = s[i-]+a[i];
     int mid = (+n)>>;
     nth_element( s+, s+mid, s++n );
     mv = s[mid];
     long long ans = , ta;
     for( int i=; i<=n; i++ ) {
         ta = s[i]-mv;
         if( ta< ) ta=-ta;
         ans += ta;
     }
     printf( "%lld\n", ans );
 }