3424: Candies (differential constraint, Dijkstra) (paired stack optimization

Surface link title

 

answer

So xy <= z x represents a large maximum ratio y z. 
If <= k1, cb <= k2 , ca <= k3 ba, ca then up to how much? Obviously it should be equal to min (k1 + k2, k3) . FIG represented by the following diagram (FIG ugly Wuguai not good) 

 

C ++ heap optimized code

// front chain to FIG StarRam + Dijkstra stack optimized 
#include <the iostream> 
#include <cstdio> 
#include <Queue> 
#include <CString>
 the using  namespace STD;
 const  int MAX = 100005 ;
 const  int MAXN = 400009 ;
 const  int INF = 0x3f3f3f3f ;
 int head [MAX], CNT = 0 ;
 int T, n-, A, B, len;
 int dist [MAX];
 BOOL VIS [MAX];
 struct Edge {                             // chain before to star 
    int next,val,to;
}Edge[MAXN];
inline void add(int u,int v,int w)
{
    Edge[cnt].to=v;
    Edge[cnt].val=w;
    Edge[cnt].next=head[u];
    head[u]=cnt++;
}
struct node
{
    int POS, dist;                         // position and distance from the point of 
    node () {}
    node(int p,int d)
    {
        pos=p;
        dist=d;
    }
    bool operator < (const node &rhs)const        //重载 < 
    {
        return dist>rhs.dist;
    }
};
void Dij(int start)
{
    priority_queue<node>que;
    for(int i=1;i<=t;i++)
    {
        dist[i]=INF;
        view [i] = false ;
    }
    dist[start]=0;
    que.push(node(start,0));
    
    while(!que.empty())
    {
        TEMP Node = que.top ();                 // priority queue elements and the minimum value of dist led array 
        que.pop ();
         int V = temp.pos;                         // filter minimum value 
        IF (VIS [V]) Continue ;                     // determines whether minimum is found, it is skipped 
        VIS [V] = to true ;
        
        for ( int I = head [V]; I = -! . 1 ; Edge I = [I] .next)         // with the minimum point of the arc from the trailing edge of updates 
        {
             int to = Edge [I] .to;
             IF (dist [to]> dist [V] + Edge [I] .val)
            {
                dist[to]=dist[v]+Edge[i].val;
                que.push(node(to,dist[to]));
            }
        }
    }
}
int main ()
{
    while(scanf("%d%d",&t,&n)!=EOF)
    {
        memset(head,-1,sizeof(head));
        for(int i=0;i<n;i++)
        {
            scanf("%d%d%d",&a,&b,&len);
            add(a,b,len);
            //add(b,a,len);
        }
        Against ( 1 );
        printf("%d\n",dist[t]);
    }
    return 0;
}

 

C ++ pairing heap optimization

#include <bits/stdc++.h>
#include<ext/pb_ds/priority_queue.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef pair<int,int> pii;
typedef __gnu_pbds::priority_queue<pii,greater<pii>,pairing_heap_tag> Heap;
const int maxn=1e5+10;
const int INF=0x3f3f3f3f;

int n,m,s;
struct Edge{
    int u,v,w;
    Edge(int _u=0,int _v=0,int _w=0){u=_u,v=_v,w=_w;}
};
vector<Edge> E;
vector<int> G[maxn];
void addedge(int u,int v,int w)
{
    E.push_back(Edge(u,v,w));
    G[u].push_back(E.size()-1);
}

int d[maxn];
void dijkstra()
{
    memset(d,0x3f,sizeof(d));

    Heap Q;
    Heap::point_iterator id[maxn];

    d[s]=0;
    id[s]=Q.push(make_pair(d[s],s));
    while(!Q.empty())
    {
        int u=Q.top().second; Q.pop();
        for(int i=0;i<G[u].size();i++)
        {
            Edge &e=E[G[u][i]]; int v=e.v;
            if(d[v]>d[u]+e.w)
            {
                d[v]=d[u]+e.w;
                if(id[v]!=0) Q.modify(id[v],make_pair(d[v],v));
                else id[v]=Q.push(make_pair(d[v],v));
            }
        }
    }
}
int main ()
{
    while(~scanf("%d%d",&n,&m)){
    s = 1;//起点
    //memset(d,0,sizeof d);
    memset(G,0,sizeof G);
    for(int i=1;i<=m;i++)
    {
        int u,v,w;
        scanf("%d%d%d",&u,&v,&w);
        addedge(u,v,w);
    }
    dijkstra();
    //for(int i=1;i<=n;i++) printf("%d%s",d[i],((i==n)?"\n":" "));
    printf("%d\n",d[n]);
    }
}