bzoj 2662

貌似和2763没鸟区别？

#include<bits/stdc++.h>
#define inc(i,l,r) for(i=l;i<=r;i++)
#define dec(i,l,r) for(i=l;i>=r;i--)
#define inf 1e9
#define mem(a) memset(a,0,sizeof(a))
#define ll long long
#define NM 50+5
using namespace std;
int read(){
    int x=0,f=1;char ch=getchar();
    while(!isdigit(ch)){if(ch=='-')f=-1;ch=getchar();}
    while(isdigit(ch))x=x*10+ch-'0',ch=getchar();
    return f*x;
}
struct edge{
    int t,v;
    edge *next;
}e[2005],*h[NM];
queue<int >q;
int d[NM][NM],n,m,p,i,x,y,t,s,ans;
bool v[NM];
void add(int x,int y,int v){
    e[++s].t=y;e[s].v=v;e[s].next=h[x];h[x]=&e[s];
}
int spfa(){
    ans=inf;
    inc(i,0,p){
        mem(v);
        v[1]++;q.push(1);d[i][1]++;
        while(!q.empty()){
            int t=q.front();q.pop();v[t]=false;
            for(edge *j=h[t];j;j=j->next){
                if(!d[i][j->t]||d[i][j->t]>d[i][t]+j->v){
                    d[i][j->t]=d[i][t]+j->v;
                    if(!v[j->t]){
                        v[j->t]++;q.push(j->t);
                    }
                }
                if(i>0)
                if(!d[i][j->t]||d[i][j->t]>d[i-1][t]+j->v/2){
                    d[i][j->t]=d[i-1][t]+j->v/2;
                    if(!v[j->t]){
                        v[j->t]++;q.push(j->t);
                    }
                }
            }
        }
        ans=min(ans,d[i][n]-1);
    }
    return ans;
}
int main(){
    n=read();m=read();p=read();
    inc(i,1,m){
        x=read();y=read();t=read();
        add(x,y,t);add(y,x,t);
    }
    printf("%d",spfa());
    return 0;
}