poj 1201

// Accepted 6736K 1625MS#include <cstdio>#include <cstring>#include <iostream>#include <vector>#include <queue>using namespace std;const int inf = 0x3f3f3f3f;const int maxn = 50000+10;int Max, Min, n;int a[maxn], b[maxn], c[maxn];int d[maxn];int inq[maxn];// 判断是否在队列中int cnt[maxn];// 判断入队的次数// bellman_ford用邻接表存储struct edge{  int from, to, cost;};vector<edge> E;vector<int> G[maxn];/*  0 <= s(i)-s(i-1) <= 1  s(bi) - s(ai)-1 <= c(i)*/void init(){  E.clear();  for(int i = 0; i < maxn; i ++){    G[i].clear();  }}void add_edge(int u, int v, int cost){  edge temp;  temp.from = u, temp.to = v, temp.cost = cost;  E.push_back(temp);  G[u].push_back(E.size()-1);}bool spfa(int src, int des){    memset(inq, 0, sizeof(inq));    memset(cnt, 0, sizeof(cnt));    queue<int> q;    for(int i = 0; i <= des; i ++){      d[i] = inf;    }    d[0] = 0;    inq[0] = 1;    q.push(0);    while(!q.empty()){      int u = q.front();      q.pop();      inq[u] = 0;      for(int i = 0; i < G[u].size(); i ++){        edge temp = E[G[u][i]];        if(d[temp.to] > d[u] + temp.cost){          d[temp.to] = d[u] + temp.cost;          if(!inq[temp.to]){            q.push(temp.to);            cnt[temp.to] ++;            inq[temp.to] = 1;            if(cnt[temp.to] > des-src+1) return false;          }        }      }    }    return true;}void bellman(int src, int des){  memset(d, 0, sizeof(inf));  d[src] = 0;  for(int i = src; i <= des; i ++){    for(int j = 0; j < E.size(); j ++){      if(d[E[j].to] > d[E[j].from] + E[j].cost){        d[E[j].to] = d[E[j].from] + E[j].cost;      }    }  }}int main(){  while(scanf("%d", &n) != EOF){    Max = -1;    Min = maxn;    init();    for(int i = 1; i <= n; i ++){      scanf("%d%d%d", &a[i], &b[i], &c[i]);      add_edge(b[i]+1, a[i], -c[i]);      if(b[i]+1 > Max) Max = b[i]+1;    }    // 仅仅只是编号    for(int i = 1; i < Max; i ++){      //add_edge(0, i, 0);      add_edge(i, i+1, 1);      add_edge(i+1, i, 0);    }    add_edge(0, Max, 0);    /*    cout << Max << endl;    for(int i = 0; i < E.size(); i ++)      cout << E[i].from << " " << E[i].to << " " << E[i].cost << endl;    for(int i = Min; i <= Max; i ++){      for(int j = 0; j < G[i].size(); j ++){        cout << i << " " << E[G[i][j]].from << " " << E[G[i][j]].to << " " <<        E[G[i][j]].cost  << endl;      }    }    */    spfa(0, Max);    //for(int i = 0; i <= Max; i ++)    //  cout << d[i] << endl;    cout << d[Max]-d[1] << endl;  }  return 0;}