2015 多校联赛 ——HDU5303（贪心）

Delicious Apples

Time Limit: 5000/3000 MS (Java/Others)    Memory Limit: 524288/524288 K (Java/Others)
Total Submission(s): 1371    Accepted Submission(s): 448

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?

1≤n,k≤105,ai≥1,a1+a2+...+an≤105
1≤L≤109
0≤x[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

 

Author

XJZX

 

Source

2015 Multi-University Training Contest 2

题意：给定一个环，以下标为处为起始点，距离起始点Xi位置种植一颗苹果树，该树有a个苹果，篮子的最大容量为K，那么求摘完全部苹果所需的最短距离。

当时大致知道方向，但是没想到具体方法。首先贪心左右半边，推出len-k时的最短路程，最后则可以直接走一圈取完。然后再与左右分别取相比较，取较小。

#include 
#include 
#include 
#include 
using namespace std;
#define MAX 100050
long long sum_left[MAX];
long long sum_right[MAX];
int l[MAX],r[MAX];

long long ans;
int Left,Right;
int n,k,len,T,a,b;

int main()
{
    scanf("%d",&T);
    while(T--)
    {
        memset(sum_left,0,sizeof(sum_left));
        memset(sum_right,0,sizeof(sum_right));

        scanf("%d%d%d",&len,&n,&k);
        Left=0,Right=0;
        for(int i=0; i