codeforces #339 div2 D

http://codeforces.com/contest/613/problem/B 题意:有n个技能,初始每个技能的level为a[i],每个技能最大level为A(不妨称为满级技能),设满级技能个数为maxnum,最小的技能level为minval,问如何将m个技能点分配到n个技能上使得cfmaxsum+cmminval (n<=1E5,a[i],A<=1E9,cf,cm<=1E3,m<=1E15)

思路:贪心。如果让有限的maxsum个技能满级的话,那么一定是让初始最大的maxsum技能满级更优。我们O(n)可以预处理一个c[i]数组,表示将i个技能变成最大值的最小花费。

然后再预处理一个前缀和数组,sum[i]表示初始最小的i个的技能的花费之和。

然后从0到n枚举变成最大值的技能的个数,在剩下的技能中二分能达到的最小值。

注意要按照原来顺序输出,所以记得记录id.

/* ***********************************************
Author :111qqz
Created Time :2016年02月20日 星期六 13时11分30秒
File Name :code/cf/#339/D.cpp
************************************************ */
 1#include <cstdio>
 2#include <cstring>
 3#include <iostream>
 4#include <algorithm>
 5#include <vector>
 6#include <queue>
 7#include <set>
 8#include <map>
 9#include <string>
10#include <cmath>
11#include <cstdlib>
12#include <ctime>
13#define fst first
14#define sec second
15#define lson l,m,rt<<1
16#define rson m+1,r,rt<<1|1
17#define ms(a,x) memset(a,x,sizeof(a))
18typedef long long LL;
19#define pi pair < int ,int >
20#define MP make_pair
 1using namespace std;
 2const double eps = 1E-8;
 3const int dx4[4]={1,0,0,-1};
 4const int dy4[4]={0,-1,1,0};
 5const int inf = 0x3f3f3f3f;
 6const int N=1E5+7;
 7LL n,A,cf,cm,m;
 8LL b[N];
 9LL c[N]; //c[i]表示将i个变为最大值需要的最少花费
10LL sum[N] ; //sum[i]表示花费最少的i个的价值和
11struct node
12{
13    LL val;
14    int id;
1    bool operator < (node b)const
2    {
3	return val>b.val;
4    }
5}a[N];
 1bool cmp (LL a,LL b)
 2{
 3    return a<b;
 4}
 5bool cmp2( node a,node b)
 6{
 7    return a.id<b.id;
 8}
 9int main()
10{
11	#ifndef  ONLINE_JUDGE 
12	freopen("code/in.txt","r",stdin);
13  #endif
14	ios::sync_with_stdio(false);
15	cin>>n>>A>>cf>>cm>>m;
16	for ( int i = 1 ; i <= n ; i++) cin>>a[i].val,a[i].id =  i,b[i] = a[i].val;
17	sort(b+1,b+n+1,cmp);
18	sort(a+1,a+n+1);
1	LL cost = 0 ;
2	c[0] = 0;
3	for ( int i = 1 ; i <= n ; i++)
4	{
5	    cost +=A-a[i].val;
6	    c[i] = cost;
7	}
8	sum[0] = 0LL;
9	for ( int i = 1 ; i <= n ; i++) sum[i] = sum[i-1] + b[i];
1	LL maxnum;
2	LL minval;
3	LL ans = -1;
4	for ( int i = 0 ; i <= n ; i++) //i表示达到最大值的有i个
5	{
6	    LL M = m;
7	    LL left = M - c[i];
8	    if (left<0) break;
	    LL l=0,r=A;
1	    while (l<r) //在剩下的n-i个数里二分最小值
2	    {
3		LL mid = (l+r+1)>>1;
4		int x= lower_bound(b+1,b+n-i+1,mid)-b-1;
5		if (mid*x-sum[x]<=left) l = mid;
6		else r = mid -1;
7	    }
1	    if (cf*i+cm*l>ans)
2	    {
3		ans = cf*i+cm*l;
4		maxnum  = i;
5		minval = l;
6	    }
7	}
1	for ( int i = 1 ; i <= maxnum ; i++) a[i].val = A;
2	for ( int i = 1 ; i <= n ; i++) if (a[i].val<minval) a[i].val = minval;
3	sort(a+1,a+n+1,cmp2);
4	cout<<ans<<endl;
5	for ( int i = 1 ; i <= n-1 ; i++) cout<<a[i].val<<" ";
6	cout<<a[n].val<<endl;
1  #ifndef ONLINE_JUDGE  
2  fclose(stdin);
3  #endif
4    return 0;
5}