为什么改了 邻接表+spfa 就re了呢？求教。。
#include <iostream>
#include <algorithm>
#include <cmath>
#include <queue>

using namespace std;

#define MAXN 20000

int ans[MAXN];
int n;//顶点数
 typedef struct NODE
 {
  //int next;
  struct NODE *next;
  int  value;
  int v;
 }node;
 node *cow[MAXN];


bool mark[MAXN];
int q[MAXN*5];//队列
int maxv;

inline void AddEdge(int s, int e,int value)
{
    node *p;
    p=(NODE*)malloc(sizeof(NODE));
    p->value=value;
    p->v=e;     
    p->next=cow[s];
    cow[s]=p;
  
}

int Spfa(int s)
{
  int front = 0, rear = 1;
  fill(ans, ans+maxv, -1);
  memset(q,sizeof(q),0);
  memset(mark,false,sizeof(mark));
  
  ans[s] = 0;
  mark[s] = true;
  q[front] = s;

  while (front != rear)
  {
   int vertex = q[front++];
   mark[vertex] = false;
   node *itor;
   
    for(itor=cow[vertex];itor;itor=itor->next)
   {
    
    int  val = ans[vertex]+itor->value;
    int nextPt = itor->v;
    if (val > ans[nextPt])
    {
     ans[nextPt] = val;

     if (!mark[nextPt])
     {
      mark[nextPt] = true;
      q[rear++] = nextPt;
     }
    }
   }
  }
  
  //for(int i=0; i<maxv; i++)cout<<ans[i];
  return ans[maxv];
 }
int main()
{

        int n, min, i, j, cal, u, k,c,temp;
        int K;
        while(scanf("%d %d", &K,&n) != EOF)
        {
                maxv = -1;
                for(i=0; i<MAXN; i++)cow[i]=NULL;
                for(k = 0; k < n; k++)
                {
                        scanf("%d%d", &i, &j);
                        i+=10001;
                        j+=10001;
                        if(i>j)temp=i,i=j,j=temp;        
                        j++;
                        if(j-i>=K)c=K;
                        else c=j-i;
                        AddEdge(i,j,c);
                        maxv = max(maxv, j);
                }
                maxv++;
                for ( i = 1; i <= maxv; ++i)
                {
                     AddEdge(i-1,i,0);
                     AddEdge(i,i-1,-1);     
                }
                int anss=Spfa(0);
                printf("%d\n", anss);
             
                for(int i=0; i<=maxv; i++)
                  if(ans[i+1]-ans[i]==1) 
                    printf("%d\n",i-10001);
                
        }
        return 0;
}