1003: [ZJOI2006]物流运输 最短路+dp

Posted 2020-11-06 walfy

https://www.lydsy.com/JudgeOnline/problem.php?id=1003

数据范围很小,怎么瞎搞都行,n方dp,然后跑出最短路暴力转移,需要注意的是不能使用的可能有多个区间

/**************************************************************
    Problem: 1003
    User: walfy
    Language: C++
    Result: Accepted
    Time:180 ms
    Memory:1400 kb
****************************************************************/
 
//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define pi acos(-1.0)
#define ll long long
#define mod 1000000007
#define C 0.5772156649
#define ls l,m,rt<<1
#define rs m+1,r,rt<<1|1
#define pil pair<int,ll>
#define pli pair<ll,int>
#define pii pair<int,int>
#define cd complex<double>
#define ull unsigned long long
#define base 1000000000000000000
#define fio ios::sync_with_stdio(false);cin.tie(0)
 
using namespace std;
 
const double eps=1e-6;
const int N=100+10,maxn=5000+10,inf=0x3f3f3f3f,INF=0x3f3f3f3f3f3f3f3f;
 
struct edge{
    int to,Next,c;
}e[maxn];
int head[N],cnt,ban[N][N];
void add(int u,int v,int c)
{
    e[cnt].to=v;
    e[cnt].c=c;
    e[cnt].Next=head[u];
    head[u]=cnt++;
}
void init()
{
    cnt=0;
    memset(head,-1,sizeof head);
}
priority_queue<pair<int,int> >q;
int dis[N],dp[N];
int n,m,K,E;
int dij(int be,int en)
{
    q.push(mp(0,1));
    memset(dis,inf,sizeof dis);
    dis[1]=0;
    while(!q.empty())
    {
        pii u=q.top();
        q.pop();
        int x=u.se;
        if(dis[x]<u.fi)continue;
        for(int i=head[x];~i;i=e[i].Next)
        {
            int To=e[i].to;
            bool ok=1;
            for(int j=be;j<=en;j++)
                if(ban[To][j])
                    ok=0;
            if(ok)
            {
                if(dis[To]>dis[x]+e[i].c)
                {
                    dis[To]=dis[x]+e[i].c;
                    q.push(mp(dis[To],To));
                }
            }
        }
    }
    if(dis[m]==inf)return -1;
    else return dis[m]*(en-be+1);
}
int main()
{
    scanf("%d%d%d%d",&n,&m,&K,&E);
    init();
    for(int i=0;i<E;i++)
    {
        int a,b,c;
        scanf("%d%d%d",&a,&b,&c);
        add(a,b,c);
        add(b,a,c);
    }
    int d;scanf("%d",&d);
    while(d--)
    {
        int p,a,b;scanf("%d%d%d",&p,&a,&b);
        for(int i=a;i<=b;i++)ban[p][i]=1;
    }
    memset(dp,inf,sizeof dp);
    dp[0]=-K;
    for(int i=1;i<=n;i++)
    {
        for(int j=0;j<i;j++)
        {
            int dis=dij(j+1,i);
            if(dis>0)dp[i]=min(dp[i],dp[j]+dis+K);
        }
    }
    printf("%d\n",dp[n]);
    return 0;
}
/********************
 
********************/

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