poj 2528 Mayor's posters

poj 2528 Mayor's posters

poj 2528Mayor's posters
http://acm.pku.edu.cn/JudgeOnline/problem?id=2528
离散化+线段树

Source Code

Problem: 2528		User: lovecanon
Memory: 760K		Time: 79MS
Language: C++		Result: Accepted

• Source Code

#include < stdio.h >
#include < stdlib.h >
#include < string .h >

int  tree[ 20002 * 3 + 1 ],seg[ 20002 ][ 2 ],a[ 20002 ],point[ 20002 ],vis[ 20002 ],tot,sum_of_point,size;

int  min( int  a, int  b){ if (a <= b)  return  a; else   return  b;}
int  max( int  a, int  b){ if (a >= b)  return  a; else   return  b;}

int  cmp( const   void   * a, const   void   * b){
     return   * ( int   * )a -* ( int   * )b;
}
int  binary_search( int  t){
     int  l = 1 ,r = sum_of_point;
     while (l <= r){
         int  m = (l + r) / 2 ;
         if (point[m] == t)  return  m;
         else   if (point[m] > t) r = m - 1 ;
         else  l = m + 1 ;
    }
     return  l;
}
void  modify( int  l, int  r, int  c, int  L, int  R, int  t){
     if (l == L && r == R || tree[t] == c) {tree[t] = c; return  ;} 
     if (tree[t] !=- 1 ) tree[t * 2 ] = tree[t * 2 + 1 ] = tree[t];
    tree[t] =- 1 ;
     int  m = (L + R) / 2 ;
     if (l < m) modify(l,min(m,r),c,L,m,t * 2 );
     if (r > m) modify(max(l,m),r,c,m,R,t * 2 + 1 );
}
void  query( int  t, int  L, int  R){
     if (tree[t] !=- 1 && tree[t] != 0 ){
         int  i;
         for (i = L;i < R;i ++ ) a[i] = tree[t];
    }
     else   if (tree[t] != 0 ){
        query(t * 2 ,L,(L + R) / 2 );
        query(t * 2 + 1 ,(L + R) / 2 ,R);    
    }
}
int  main(){
     int  i,T,N,x,y;
    scanf( " %d " , & T);
     while (T -- ){
        scanf( " %d " , & N);
        tot = 0 ;
         for (i = 1 ;i <= N;i ++ ){
            scanf( " %d%d " , & x, & y);
            seg[i][ 0 ] = x;seg[i][ 1 ] = y + 1 ;
            a[ ++ tot] = x;a[ ++ tot] = y + 1 ;
        }
        qsort(a + 1 ,tot, sizeof (a[ 0 ]),cmp);
        sum_of_point = 0 ;point[ ++ sum_of_point] = a[ 1 ];
        
         for (i = 2 ;i <= tot;i ++ )
             if (a[i] != a[i - 1 ]) point[ ++ sum_of_point] = a[i];

  
        size = sum_of_point;
        tree[ 1 ] = 0 ;
         for (i = 1 ;i <= N;i ++ ){
            x = binary_search(seg[i][ 0 ]);
            y = binary_search(seg[i][ 1 ]);
            modify(x,y,i, 1 ,size, 1 );
        }
        memset(a, 0 , sizeof (a));
        memset(vis, 0 , sizeof (vis));
        query( 1 , 1 ,size);
         int  tmp =- 2 ,ret = 0 ;
         for (i = 1 ;i < size;i ++ ){
             if (a[i] == tmp)  continue ;
             else {
                tmp = a[i];
                 if (tmp != 0 &&! vis[tmp]) {vis[tmp] = 1 ;ret ++ ;}
            }
        }
        printf( " %d\n " ,ret);
    }
     return   0 ;
}