Modular Production Line

本文探讨了一种在有限时间和资源下,通过优化生产线部分区段的运作,以最大化子产品价值的方法。采用最小费用最大流算法,通过对生产线的离散化处理和构建网络流模型,实现了在满足限制条件下的收益最大化。

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题目描述

An automobile factory has a car production line. Now the market is oversupply and the production line is often shut down. To make full use of resources, the manager divides the entire production line into N parts (1...N). Some continuous parts can produce sub-products. And each of sub-products has their own value. The manager will use spare time to produce sub-products to make money. Because of the limited spare time, each part of the production line could only work at most K times. And Because of the limited materials, each of the sub-products could be produced only once. The manager wants to know the maximum value could he make by produce sub-products.

 

输入

The first line of input is T, the number of test case.
The first line of each test case contains three integers, N, K and M.(M is the number of different sub-product).
The next M line each contain three integers Ai, Bi, Wi describing a sub-product. The sub-product has value Wi. Only Ai to Bi parts work simultaneously will the sub-product be produced(include Ai to Bi).

1 ≤ T ≤ 100
1 ≤ K ≤ M ≤ 200
1 ≤ N ≤ 10^5
1 ≤ Ai ≤ Bi ≤ N
1 ≤ Wi ≤10^5

 

 

输出

For each test case output the maximum value in a separate line.

 

样例输入

复制样例数据

4
10 1 3
1 2 2
2 3 4
3 4 8
10 1 3
1 3 2
2 3 4
3 4 8
100000 1 3
1 100000 100000
1 2 3
100 200 300
100000 2 3
1 100000 100000
1 150 301
100 200 300

样例输出

10
8
100000
100301

最长 k 可重区间集

https://www.cnblogs.com/hongyj/p/9433635.html

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
const long long INF=1e9;
const int maxn = 510;
//spfa最小费用最大流模板
struct edge
{
    int to,nex,cap,cost,flow;
} G[maxn*3];
int dis[maxn],pre[maxn],head[maxn],tot,V;
bool vis[maxn];

void addedge(int u,int v,int cap,int cost)
{
    G[tot].to=v;
    G[tot].cap=cap;
    G[tot].cost=cost;
    G[tot].flow=0;
    G[tot].nex=head[u];
    head[u]=tot;
    ++tot;

    G[tot].to=u;
    G[tot].cap=0;
    G[tot].cost=-cost;
    G[tot].flow=0;
    G[tot].nex=head[v];
    head[v]=tot;
    ++tot;
}
void init(int n)
{
    V=n;
    tot=0;
    memset(head,-1,sizeof(head));
}
bool spfa(int s,int t)
{
    queue<int>q;
    for (int i = 0; i < V; i++)
    {
        dis[i] = INF;
        vis[i] = false;
        pre[i] = -1;
    }
    dis[s] = 0;
    vis[s] = true;
    q.push(s);
    while (!q.empty())
    {
        int u = q.front();
        q.pop();
        vis[u] = false;
        for (int i = head[u]; i !=-1; i = G[i].nex)
        {
            int v = G[i].to;
            if (G[i].cap>G[i].flow&&dis[v]>dis[u] + G[i].cost)
            {
                dis[v] = dis[u] + G[i].cost;
                pre[v] = i;
                if (!vis[v])
                {
                    vis[v] = true;
                    q.push(v);
                }
            }
        }
    }
    if (pre[t] == -1)
    {
        return false;
    }
    else
    {
        return true;
    }
}
int mcmf(int s, int t, int &cost)
{
    int flow = 0;
    cost = 0;
    while (spfa(s, t))
    {
        int minn = INF;
        for (int i = pre[t]; i !=-1; i = pre[G[i ^ 1].to])
        {
            if (minn>G[i].cap - G[i].flow)
            {
                minn = G[i].cap - G[i].flow;
            }
        }
        for (int i = pre[t]; i!=-1 ; i = pre[G[i ^ 1].to])
        {
            G[i].flow += minn;
            G[i ^ 1].flow -= minn;
            cost += G[i].cost*minn;
        }
        flow += minn;
    }
    return flow;
}

struct node
{
    int l, r;
    int val;
};//用于离散化
int x, y, n, m;
int k, v;
node a[maxn];
int b[maxn];
map<int, int> mp;
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d%d", &n, &k, &m);
        int cnt = 1;
        mp.clear();
        for (int i = 0; i < m; i++)
        {
            scanf("%d%d%d", &a[i].l, &a[i].r, &a[i].val);
            b[i * 2] = a[i].l;
            b[i * 2 + 1] = a[i].r;
        }
        sort(b, b + m * 2);
        mp[b[0]] = cnt;
        for (int i = 1; i < m * 2; i++)
        {
            if (b[i] != b[i - 1])
            {
                mp[b[i]] = cnt++;
            }
        }
        init(cnt + 2);
        int S = cnt + 1, T = cnt;
        for (int i = 0; i < m; i++)
        {
            addedge(mp[a[i].l] - 1, mp[a[i].r], 1, -a[i].val);
        }
        addedge(S, 0, k, 0);
        for (int i = 0; i < cnt; i++)
        {
            addedge(i, i + 1, INF, 0);
        }
        int ans = 0;
        mcmf(S, T, ans);
        printf("%d\n", -ans);
    }
    return 0;
}

 

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