1 #include <iostream>
 2 #include <cstdio>
 3 #include <cmath>
 4 #include <cstring>
 5 #include <queue>
 6 using namespace std;
 7 #define N 1000001
 8 #define INF 0x7fffff
 9 struct node
10 {
11     int u,v,next,w;
12 }edge[N];
13 int first[N],t,maxz,minz;
14 int in[N],d[N];
15 void CL()
16 {
17     t = 1;
18     memset(first,-1,sizeof(first));
19 }
20 void add(int u,int v,int w)
21 {
22     edge[t].u = u;
23     edge[t].v = v;
24     edge[t].w = w;
25     edge[t].next = first[u];
26     first[u] = t;
27     t ++;
28 }
29  void spfa(int str)//spfa模版
30  {
31      int i,v,u;
32      queue<int> que;
33      for(i = minz;i <= maxz;i ++)
34      {
35          in[i] = 0;
36          d[i] = -INF;
37      }
38      que.push(str);
39      in[str] = 1;
40      d[str] = 0;
41      while(!que.empty())
42      {
43          u = que.front();
44          in[u] = 0;
45          que.pop();
46          for(i = first[u];i != -1;i = edge[i].next)
47          {
48              v = edge[i].v;
49              if(d[v] < d[u]+edge[i].w)
50              {
51                  d[v] = d[u]+edge[i].w;
52                  if(!in[v])
53                  {
54                      in[v] = i;
55                      que.push(v);
56                  }
57              }
58          }
59      }
60  }
61 int main()
62 {
63     int n,i,sv,ev,w;
64     maxz = -1;
65     minz = 50001;
66     CL();
67     scanf("%d",&n);
68     for(i = 1;i <= n;i ++)
69     {
70         scanf("%d%d%d",&sv,&ev,&w);
71         minz = min(sv,minz);
72         maxz = max(ev+1,maxz);
73         add(sv,ev+1,w);//建图
74     }
75     for(i = minz;i <= maxz;i ++)
76     {
77         add(i,i+1,0);//建图
78         add(i+1,i,-1);
79     }
80     spfa(minz);
81     printf("%d\n",d[maxz]);
82     return 0;
83 }