HDU---4109指令安排

#include<iostream>
#include<stack>
#include<string.h>
using namespace std;
const int maxn = 1000+10;
int map[maxn][maxn],topo[maxn],in[maxn],label[maxn],n,m;//label:标记执行的时间. 
stack<int> s; 
void TopoSort(){
  //int cnt = 0;
  for(int i = 0; i < n; i++){
    if(!in[i]){//入度为0的进栈 
      s.push(i);
      label[i] = 1;//标记执行时间为1 
    }
  } 
  while(!s.empty()) {
    int x = s.top();
    s.pop();
    //topo[++cnt] = x;
    for(int i = 0;i  < n; i++){
      if(map[x][i]){
        if(label[i] < label[x]+map[x][i]){//最常路径松弛操作. 
          label[i] = label[x]+map[x][i]; 
        }
        in[i]--;
        if(!in[i]){
          s.push(i);
        }
      }
    }
  }
} 
int main()
{
  int u,v,w, maxt;
  while(cin>>n>>m){
    //初始化 
    memset(map,0,sizeof(map));
    memset(topo,0,sizeof(topo));
    memset(in,0,sizeof(in));
    memset(label,0,sizeof(label));
    maxt = 0;
    for(int i = 1;i <= m; i++){
      cin>>u>>v>>w;
      map[u][v] = w;
      in[v]++; 
    }
    TopoSort();
    for(int i = 0; i < n; i++){
      if(label[i] > maxt){
        maxt = label[i];
      }
    } 
    cout<<maxt<<endl;
  }
  return 0;
}