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dis[2*i-1]表示第i个任务的起始时间 dis[2*i]表示第i个任务的终止时间

可得:

1 dis[2*i]-dis[2*i-1]=val[i]

2 FAS dis[2*u]-dis[2*v-1]>=1

3 FAF dis[2*u]-dis[2*v]>=1

4 SAF dis[2*u-1]-dis[2*v]>=1

5 SAS dis[2*u-1]-dis[2*v-1]>=1

建图 spfa求最长路即可

另外还要注意保证图的连通性 可以建立一个超级源点

#include <bits/stdc++.h>
using namespace std;
#define N 0x3f3f3f3f

struct node
{
    int v;
    int w;
    int next;
};

queue <int> que;
node edge[1000010];
int first[200010],val[200010],dis[200010],book[200010],cnt[200010];
int n,m,num;

void addedge(int u,int v,int w)
{
    edge[num].v=v;
    edge[num].w=w;
    edge[num].next=first[u];
    first[u]=num++;
    return;
}

void spfa()
{
    int i,u,v,w,flag;
    while(!que.empty()) que.pop();
    for(i=1;i<=2*n;i++)
    {
        dis[i]=-N;
        book[i]=0;
        cnt[i]=0;
    }
    que.push(0);
    dis[0]=0,book[0]=1,cnt[0]=1;
    flag=1;
    while(!que.empty())
    {
        u=que.front();
        que.pop();
        book[u]=0;
        for(i=first[u];i!=-1;i=edge[i].next)
        {
            v=edge[i].v,w=edge[i].w;
            if(dis[v]<dis[u]+w)
            {
                dis[v]=dis[u]+w;
                if(!book[v])
                {
                    que.push(v);
                    book[v]=1,cnt[v]++;
                    if(cnt[v]>2*n+1)
                    {
                        flag=0;
                        break;
                    }
                }
            }
        }
        if(!flag) break;
    }
    if(flag)
    {
        for(i=1;i<=n;i++)
        {
            printf("%d %d\n",i,dis[2*i-1]);
        }
    }
    else
    {
        printf("impossible\n");
    }
    return;
}

int main()
{
    int cas,i,u,v,res;
    char ch[10];
    cas=1;
    while(scanf("%d",&n)!=EOF)
    {
        if(n==0) break;
        memset(first,-1,sizeof(first));
        num=0;
        for(i=1;i<=n;i++)
        {
            scanf("%d",&val[i]);
            addedge(2*i-1,2*i,val[i]);
            addedge(2*i,2*i-1,-val[i]);
        }
        while(1)
        {
            scanf("%s",ch);
            if(ch[0]=='#') break;
            scanf("%d%d",&u,&v);
            if(strcmp(ch,"FAS")==0) addedge(2*v-1,2*u,0);
            else if(strcmp(ch,"FAF")==0) addedge(2*v,2*u,0);
            else if(strcmp(ch,"SAF")==0) addedge(2*v,2*u-1,0);
            else addedge(2*v-1,2*u-1,0);
        }
        for(i=1;i<=2*n;i+=2)
        {
            addedge(0,i,0);
        }
        printf("Case %d:\n",cas++);
        spfa();
        printf("\n");
    }
    return 0;
}