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POJ - 3616 Milking Time (動態規劃)

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Bessie is such a hard-working cow. In fact, she is so focused on maximizing her productivity that she decides to schedule her next N (1 ≤ N ≤ 1,000,000) hours (conveniently labeled 0..N-1) so that she produces as much milk as possible.

Farmer John has a list of M (1 ≤ M ≤ 1,000) possibly overlapping intervals in which he is available for milking. Each interval i

has a starting hour (0 ≤ starting_houriN), an ending hour (starting_houri < ending_houriN), and a corresponding efficiency (1 ≤ efficiencyi ≤ 1,000,000) which indicates how many gallons of milk that he can get out of Bessie in that interval. Farmer John starts and stops milking at the beginning of the starting hour and ending hour, respectively. When being milked, Bessie must be milked through an entire interval.

Even Bessie has her limitations, though. After being milked during any interval, she must rest R (1 ≤ RN) hours before she can start milking again. Given Farmer Johns list of intervals, determine the maximum amount of milk that Bessie can produce in the N hours.

Input

* Line 1: Three space-separated integers: N

, M, and R
* Lines 2..M+1: Line i+1 describes FJ‘s ith milking interval withthree space-separated integers: starting_houri , ending_houri , and efficiencyi

Output

* Line 1: The maximum number of gallons of milk that Bessie can product in the Nhours

Sample Input

12 4 2
1 2 8
10 12 19
3 6 24
7 10 31

Sample Output

43

題意:
給出m個取奶時間段和該時間段內的取奶量,每次取奶之後需要休息r個時間段,問最大取奶量
思路:
按時間段右端點排序。
dp[i]表示第i個時間段取奶之後的最大取奶量。
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#include<iostream>
#include<algorithm>
#include<vector>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<ctime>
#define fuck(x) cout<<#x<<" = "<<x<<endl;
#define ls (t<<1)
#define rs ((t<<1)+1)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const int maxn = 100086;
const int inf = 2.1e9;
const ll Inf = 999999999999999999;
const int mod = 1000000007;
const double eps = 1e-6;
const double pi = acos(-1);
int n,m,r;
struct node{
    int l,r,v;
}a[1024];
int dp[maxn];
bool cmp(node a,node b){
    return a.r<b.r;
}

int main()
{
//    ios::sync_with_stdio(false);
//    freopen("in.txt","r",stdin);

    scanf("%d%d%d",&n,&m,&r);
    for(int i=1;i<=m;i++){
        scanf("%d%d%d",&a[i].l,&a[i].r,&a[i].v);
    }
    sort(a+1,a+1+m,cmp);
    int ans=0;
    for(int i=1;i<=m;i++){
        dp[i]=a[i].v;
        for(int j=1;j<i;j++){
            if(a[j].r+r<=a[i].l){dp[i]=max(dp[i],dp[j]+a[i].v);}
        }
        ans=max(ans,dp[i]);
    }
    printf("%d\n",ans);
    return 0;
}
View Code

POJ - 3616 Milking Time (動態規劃)