BZOJ1104 : [POI2007]洪水pow

#include<cstdio>
#define N 1010
int n,m,i,j,k,x,y,a[N][N],id[N][N],f[N*N],v[N*N],cnt,dx[4]={-1,1,0,0},dy[4]={0,0,-1,1},ans;
struct E{int x,y;E*nxt;}*g[N],*h[N],pool[N*N*2],*cur=pool,*p;
inline void addg(int z,int x,int y){p=cur++;p->x=x;p->y=y;p->nxt=g[z];g[z]=p;}
inline void addh(int z,int x,int y){p=cur++;p->x=x;p->y=y;p->nxt=h[z];h[z]=p;}
inline void read(int&a){
  char c;bool f=0;a=0;
  while(!((((c=getchar())>=‘0‘)&&(c<=‘9‘))||(c==‘-‘)));
  if(c!=‘-‘)a=c-‘0‘;else f=1;
  while(((c=getchar())>=‘0‘)&&(c<=‘9‘))(a*=10)+=c-‘0‘;
  if(f)a=-a;
}
int F(int x){return f[x]==x?x:f[x]=F(f[x]);}
inline void merge(int x,int y){if(F(x)!=F(y))v[f[y]]|=v[f[x]],f[f[x]]=f[y];}
int main(){
  for(read(n),read(m),i=1;i<=n;i++)for(j=1;j<=m;j++){
    read(a[i][j]);
    if(a[i][j]>0)addg(a[i][j],i,j);else a[i][j]=-a[i][j];
    id[i][j]=++cnt,addh(a[i][j],i,j);
  }
  for(i=1;i<=cnt;i++)f[i]=i;
  for(i=0;i<=1000;i++){
    for(p=h[i];p;p=p->nxt)for(k=0;k<4;k++){
      x=p->x+dx[k],y=p->y+dy[k];
      if(!id[x][y]||a[x][y]>a[p->x][p->y])continue;
      merge(id[p->x][p->y],id[x][y]);
    }
    for(p=g[i];p;p=p->nxt)if(!v[F(id[p->x][p->y])])v[f[id[p->x][p->y]]]=1,ans++;
  }
  return printf("%d",ans),0;
}