poj2104

快排，然后从左至右找到第c个在区间内的数。

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      #include 
    
      <
    
      iostream
    
      >
    
      
#include 
    
      <
    
      cstdio
    
      >
    
      
#include 
    
      <
    
      cstdlib
    
      >
    
      
#include 
    
      <
    
      cstring
    
      >
    
      
#include 
    
      <
    
      algorithm
    
      >
    
      

    
      using
    
       
    
      namespace
    
       std;


    
      #define
    
       maxn 100005
    
      


    
      struct
    
       Elem
{
 
    
      int
    
       p, v;
}f[maxn];


    
      bool
    
       
    
      operator
    
       
    
      <
    
       (
    
      const
    
       Elem 
    
      &
    
      a, 
    
      const
    
       Elem 
    
      &
    
      b)
{
 
    
      return
    
       a.v 
    
      <
    
       b.v;
}


    
      int
    
       main()
{

    
      //
    
       freopen("t.txt", "r", stdin);
    
      

    
       
    
      int
    
       n, m;
 scanf(
    
      "
    
      %d%d
    
      "
    
      , 
    
      &
    
      n, 
    
      &
    
      m);
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      0
    
      ; i 
    
      <
    
       n; i
    
      ++
    
      )
 {
 scanf(
    
      "
    
      %d
    
      "
    
      , 
    
      &
    
      f[i].v);
 f[i].p 
    
      =
    
       i 
    
      +
    
       
    
      1
    
      ;
 }
 sort(f, f 
    
      +
    
       n);
 
    
      while
    
       (m
    
      --
    
      )
 {
 
    
      int
    
       a, b, c;
 scanf(
    
      "
    
      %d%d%d
    
      "
    
      , 
    
      &
    
      a, 
    
      &
    
      b, 
    
      &
    
      c);
 
    
      int
    
       pos 
    
      =
    
       
    
      -
    
      1
    
      ;
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      0
    
      ; i 
    
      <
    
       c; i
    
      ++
    
      )
 {
 pos
    
      ++
    
      ;
 
    
      while
    
       (f[pos].p 
    
      >
    
       b 
    
      ||
    
       f[pos].p 
    
      <
    
       a)
 pos
    
      ++
    
      ;
 }
 printf(
    
      "
    
      %d\n
    
      "
    
      , f[pos].v);
 }
 
    
      return
    
       
    
      0
    
      ;
}