POJ 2823 Sliding Window

很CHUO的代码

用的是单调队列

还有更好的做法 以后补上

  
    

   
     #include 
   
     <
   
     stdio.h
   
     >
   
     


   
     struct
   
      Queue{
 
   
     int
   
      idx, val;
}que[
   
     1000000
   
     ];

   
     int
   
      a[
   
     1000000
   
     ];

   
     int
   
      head, tail;


   
     int
   
      main(){
 
   
     int
   
      n, k;
 scanf(
   
     "
   
     %d%d
   
     "
   
     ,
   
     &
   
     n, 
   
     &
   
     k);
 
   
     for
   
     (
   
     int
   
      i 
   
     =
   
      
   
     0
   
     ; i 
   
     <
   
      n; 
   
     ++
   
     i){
 scanf(
   
     "
   
     %d
   
     "
   
     ,
   
     &
   
     a[i]);
 }
 
   
     //
   
      k 为1时候的特殊情况， 还有更好的做法..
   
     

   
      
   
     if
   
     ( k 
   
     ==
   
      
   
     1
   
      ){
 
   
     for
   
     (
   
     int
   
      i 
   
     =
   
      
   
     0
   
     ; i 
   
     <
   
      n; 
   
     ++
   
     i){
 
   
     if
   
     ( i )
 printf(
   
     "
   
      
   
     "
   
     );
 printf(
   
     "
   
     %d
   
     "
   
     ,a[i]);
 } 
 printf(
   
     "
   
     \n
   
     "
   
     );
 
   
     for
   
     (
   
     int
   
      i 
   
     =
   
      
   
     0
   
     ; i 
   
     <
   
      n; 
   
     ++
   
     i){
 
   
     if
   
     ( i )
 printf(
   
     "
   
      
   
     "
   
     );
 printf(
   
     "
   
     %d
   
     "
   
     ,a[i]);
 } 
 printf(
   
     "
   
     \n
   
     "
   
     );
 
   
     return
   
      
   
     0
   
     ;
 }
 head 
   
     =
   
      tail 
   
     =
   
      
   
     0
   
     ;
 que[tail].val 
   
     =
   
      a[
   
     0
   
     ];
 que[tail].idx 
   
     =
   
      
   
     0
   
     ;
 
   
     bool
   
      first 
   
     =
   
      
   
     true
   
     ;
 
   
     for
   
     (
   
     int
   
      i 
   
     =
   
      
   
     1
   
     ; i 
   
     <
   
      n; 
   
     ++
   
     i){
 
 
   
     while
   
     ( head 
   
     <=
   
      tail 
   
     &&
   
      que[tail].val 
   
     >
   
      a[i] ){
 tail
   
     --
   
     ;
 }
 tail
   
     ++
   
     ;
 que[tail].val 
   
     =
   
      a[i];
 que[tail].idx 
   
     =
   
      i;
 
   
     while
   
     ( i 
   
     -
   
      que[head].idx 
   
     >=
   
      k ){
 head
   
     ++
   
     ;
 }
 
   
     if
   
     ( i 
   
     >=
   
      k 
   
     -
   
      
   
     1
   
      ){
 
   
     if
   
     ( first )
 first 
   
     =
   
      
   
     false
   
     ;
 
   
     else
   
     
 printf(
   
     "
   
      
   
     "
   
     );
 printf(
   
     "
   
     %d
   
     "
   
     ,que[head].val);
 }
 }
 printf(
   
     "
   
     \n
   
     "
   
     );
 head 
   
     =
   
      tail 
   
     =
   
      
   
     0
   
     ;
 que[tail].val 
   
     =
   
      a[
   
     0
   
     ];
 que[tail].idx 
   
     =
   
      
   
     0
   
     ;
 first 
   
     =
   
      
   
     true
   
     ;
 
   
     for
   
     (
   
     int
   
      i 
   
     =
   
      
   
     1
   
     ; i 
   
     <
   
      n; 
   
     ++
   
     i){
 
 
   
     while
   
     ( head 
   
     <=
   
      tail 
   
     &&
   
      que[tail].val 
   
     <
   
      a[i] ){
 tail
   
     --
   
     ;
 }
 tail
   
     ++
   
     ;
 que[tail].val 
   
     =
   
      a[i];
 que[tail].idx 
   
     =
   
      i;
 
   
     if
   
     ( i 
   
     -
   
      que[head].idx 
   
     >=
   
      k ){
 head
   
     ++
   
     ;
 }
 
   
     if
   
     ( i 
   
     >=
   
      k 
   
     -
   
      
   
     1
   
      ){
 
   
     if
   
     ( first )
 first 
   
     =
   
      
   
     false
   
     ;
 
   
     else
   
     
 printf(
   
     "
   
      
   
     "
   
     );
 printf(
   
     "
   
     %d
   
     "
   
     ,que[head].val);
 }
 
 }
 printf(
   
     "
   
     \n
   
     "
   
     );
 
   
     return
   
      
   
     0
   
     ;
}