Delicious Apples (hdu 5303 贪心+枚举)

Delicious Apples

Time Limit: 5000/3000 MS (Java/Others)    Memory Limit: 524288/524288 K (Java/Others)
Total Submission(s): 395    Accepted Submission(s): 122


Problem Description
There are n apple trees planted along a cyclic road, which is L metres long. Your storehouse is built at position 0 on that cyclic road.
The ith tree is planted at position xi, clockwise from position 0. There are ai delicious apple(s) on the ith tree.

You only have a basket which can contain at most K apple(s). You are to start from your storehouse, pick all the apples and carry them back to your storehouse using your basket. What is your minimum distance travelled?

1n,k105,ai1,a1+a2+...+an105
1L109
0x[i]L

There are less than 20 huge testcases, and less than 500 small testcases.
 

Input
First line: t, the number of testcases.
Then t testcases follow. In each testcase:
First line contains three integers, L,n,K.
Next n lines, each line contains xi,ai.
 

Output
Output total distance in a line for each testcase.
 

Sample Input

2 10 3 2 2 2 8 2 5 1 10 4 1 2 2 8 2 5 1 0 10000
 

Sample Output

18 26
 

Source
2015 Multi-University Training Contest 2
 

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题意:在一个圆上有n个苹果树,告诉苹果树的位置和每棵树上的苹果个数,还有一个容量为K的篮子,用篮子去摘苹果,起点在位置0,反复去摘直到把所有的苹果都摘回到0,问走的最短距离为多少。

思路:首先将圆一分为二,在圆形两侧能拿满的话肯定就是只走半边再回去,这样比走整圈划算,另外还要想到最后两边都不足K个了,这个时候最多需要走一个整圈,我们不知道这个整圈拿了哪几个苹果,那么就枚举K个。比赛时只是想到了贪心,最后那一部分没有枚举,另外这里的苹果进行了离散化,因为苹果总数只有1e5,大大简化了代码,自己当时写的太冗余=-=


代码:

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#pragma comment (linker,"/STACK:102400000,102400000")
#define pi acos(-1.0)
#define eps 1e-6
#define lson rt<<1,l,mid
#define rson rt<<1|1,mid+1,r
#define FRE(i,a,b)  for(i = a; i <= b; i++)
#define FREE(i,a,b) for(i = a; i >= b; i--)
#define FRL(i,a,b)  for(i = a; i < b; i++)
#define FRLL(i,a,b) for(i = a; i > b; i--)
#define mem(t, v)   memset ((t) , v, sizeof(t))
#define sf(n)       scanf("%d", &n)
#define sff(a,b)    scanf("%d %d", &a, &b)
#define sfff(a,b,c) scanf("%d %d %d", &a, &b, &c)
#define pf          printf
#define DBG         pf("Hi\n")
typedef long long ll;
using namespace std;

#define INF 0x3f3f3f3f
#define mod 1000000009
const int maxn = 1e5+10;
const int MAXN = 2005;
const int N = 1005;

ll Len,n,k,cnt;
ll pos[maxn],dp_l[maxn],dp_r[maxn]; //dp[i]表示拿完前i个苹果要走的的距离和
vectorposl,posr;

int main()
{
#ifndef ONLINE_JUDGE
    freopen("C:/Users/lyf/Desktop/IN.txt","r",stdin);
#endif
    ll i,j,t;
    scanf("%lld",&t);
    ll x,num;
    while (t--)
    {
        cnt=1;
        scanf("%lld%lld%lld",&Len,&n,&k);
        posl.clear();
        posr.clear();
        for (i=0;i


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