【Vijos1404】遭遇战

题面

https://vijos.org/p/1404

题解

#include<cstdio>
#include<iostream>
#include<cstring>
#include<vector>
#include<queue>
#define N 90500
#define ri register int
#define LL long long
using namespace std;

int n,s,e,l,r,c;
LL dis[N];
vector<int> to[N],len[N];
bool vis[N];

inline void add_edge(int z,int y,int x) {
  to[z].push_back(y); len[z].push_back(x);
}

struct node {
  int u; LL d;
  bool operator < (const node &rhs) const {
    return d>rhs.d;
  }
};
priority_queue<node> q;

LL dij() {
  memset(dis,0x3f,sizeof(dis));
  dis[s]=0;
  q.push((node){s,0});
  while (!q.empty()) {
    node cur=q.top(); q.pop();
    int x=cur.u;
    if (vis[x]) continue;
    vis[x]=1;
    for (ri i=0;i<to[x].size();i++) {
      int y=to[x][i];
      if (dis[y]>dis[x]+len[x][i]) {
        dis[y]=dis[x]+len[x][i];
        q.push((node){y,dis[y]});
      }
    }
  }
  return dis[e+1];
}

int main(){
  scanf("%d %d %d",&n,&s,&e);
  for (ri i=1;i<=n;i++) {
    scanf("%d %d %d",&l,&r,&c);
    add_edge(l,r+1,c);
  }
  for (ri i=1;i<N;i++) add_edge(i,i-1,0);
  LL ans=dij();
  if (ans>1e17) puts("-1"); else printf("%lld
",ans);
  return 0;
}