POJ 3169.Layout 最短路

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<map>
#include<queue>
#include<stack>
#include<vector>
#include<set>
using namespace std;
typedef pair<int,int> P;
typedef long long ll;
const int maxn=1e5+100,inf=0x3f3f3f3f,mod=1e9+7;
const ll INF=1e13+7;
struct edge
{
    int from,to;
    int cost;
};
int cou=0;
edge es[maxn];
vector<edge>G[maxn];
int used[maxn];
priority_queue<P,vector<P>,greater<P> >que;
void addedge(int u,int v,int w)
{
    cou++;
    edge e;
    e.from=u,e.to=v,e.cost=w;
    es[cou].from=u,es[cou].to=v,es[cou].cost=w;
    G[u].push_back(e);
}
int n,ml,md;
int al[maxn],bl[maxn],dl[maxn];
int ad[maxn],bd[maxn],dd[maxn];
int d[maxn];
void ford()
{
    for(int i=1; i<=n; i++) d[i]=inf;
    d[1]=0;
    for(int t=1; t<n; t++)
    {
        for(int i=1; i<n; i++)
            if(d[i+1]<inf) d[i]=min(d[i],d[i+1]);
        for(int i=1; i<=ml; i++)
            if(d[al[i]]<inf) d[bl[i]]=min(d[bl[i]],d[al[i]]+dl[i]);
        for(int i=1; i<=md; i++)
            if(d[bd[i]]<inf)  d[ad[i]]=min(d[ad[i]],d[bd[i]]-dd[i]);
    }
    if(d[1]<0) cout<<-1<<endl;
    else if(d[n]>=inf) cout<<-2<<endl;
    else cout<<d[n]<<endl;
}
int main()
{
    int a,b,d;
    scanf("%d%d%d",&n,&ml,&md);
    for(int i=1; i<n; i++) addedge(i+1,i,0);
    for(int i=1; i<=ml; i++)
        scanf("%d%d%d",&al[i],&bl[i],&dl[i]);
    for(int i=1; i<=md; i++)
        scanf("%d%d%d",&ad[i],&bd[i],&dd[i]);
    ford();
    return 0;
}
/*
4 3 0
1 3 10
2 4 20
2 3 3
*/