HDU 1160 FatMouse's Speed（最长递减子序列变形）

题目地址：​ ​点击打开链接​​

题意：给一堆老鼠，求一个最大的子集，子集的特点是从开头到结尾重量严格递增，速度严格递减

思路：先给所有老鼠按重量递增排个序，然后对速度求最长递减子序列

AC代码：

登录后复制

      
      

       
       #include <iostream>
       
       

       
       #include <cstring>
       
       

       
       #include <cstdio>
       
       

       
       #include <cstdlib>
       
       

       
       #include <algorithm>
       
       

       
       

       
       using 
       
       namespace 
       
       std;
       
       

       
       

       
       int 
       
       dp[
       
       1001],
       
       pre[
       
       1001];
       
       

       
       

       
       struct 
       
       mouse
       
       
{
       
       
    
       
       int 
       
       weight,
       
       speed,
       
       num;
       
       
}
       
       mou[
       
       1001];
       
       

       
       

       
       int 
       
       cmp(
       
       const 
       
       void 
       
       *
       
       _a,
       
       const 
       
       void 
       
       *
       
       _b)
       
       
{
       
       
    
       
       mouse 
       
       *
       
       a 
       
       = (
       
       mouse
       
       *)
       
       _a;
       
       
    
       
       mouse 
       
       *
       
       b 
       
       = (
       
       mouse
       
       *)
       
       _b;
       
       
    
       
       if(
       
       a
       
       ->
       
       weight 
       
       != 
       
       b
       
       ->
       
       weight)
       
       
        
       
       return 
       
       a
       
       ->
       
       weight 
       
       - 
       
       b
       
       ->
       
       weight;
       
       
    
       
       return 
       
       b
       
       ->
       
       speed 
       
       - 
       
       a
       
       ->
       
       speed;
       
       
}
       
       

       
       

       
       void 
       
       output(
       
       int 
       
       i)
       
       
{
       
       
    
       
       if(
       
       i 
       
       == 
       
       0)
       
       
        
       
       return;
       
       
    
       
       output(
       
       pre[
       
       i]);
       
       
    
       
       printf(
       
       "%d\n",
       
       mou[
       
       i].
       
       num);
       
       
}
       
       

       
       

       
       int 
       
       main()
       
       
{
       
       
    
       
       int 
       
       i,
       
       j,
       
       n 
       
       = 
       
       1,
       
       max 
       
       = 
       
       0,
       
       l;
       
       
    
       
       while(
       
       scanf(
       
       "%d%d",
       
       &
       
       mou[
       
       n].
       
       weight,
       
       &
       
       mou[
       
       n].
       
       speed) 
       
       != 
       
       EOF)
       
       
    {
       
       
        
       
       mou[
       
       n].
       
       num 
       
       = 
       
       n;
       
       
        
       
       n
       
       ++;
       
       
    }
       
       
    
       
       memset(
       
       dp,
       
       0,
       
       sizeof(
       
       dp));
       
       
    
       
       memset(
       
       pre,
       
       0,
       
       sizeof(
       
       pre));
       
       
    
       
       qsort(
       
       mou
       
       +
       
       1,
       
       n
       
       -
       
       1,
       
       sizeof(
       
       mouse),
       
       cmp);
       
       
    
       
       dp[
       
       1] 
       
       = 
       
       1;
       
       
    
       
       for(
       
       i
       
       =
       
       2; 
       
       i
       
       <=
       
       n; 
       
       i
       
       ++)
       
       
    {
       
       
        
       
       for(
       
       j
       
       =
       
       1; 
       
       j
       
       <
       
       i; 
       
       j
       
       ++)
       
       
        {
       
       
            
       
       if(
       
       mou[
       
       i].
       
       weight 
       
       > 
       
       mou[
       
       j].
       
       weight 
       
       && 
       
       mou[
       
       i].
       
       speed 
       
       < 
       
       mou[
       
       j].
       
       speed 
       
       && 
       
       dp[
       
       i] 
       
       < 
       
       dp[
       
       j])
       
       //要严格递增，所以要再比较一次
       
       
            {
       
       
                
       
       dp[
       
       i] 
       
       = 
       
       dp[
       
       j];
       
       
                
       
       pre[
       
       i] 
       
       = 
       
       j;
       
       
            }
       
       
        }
       
       
        
       
       dp[
       
       i]
       
       ++;
       
       
    }
       
       
    
       
       for(
       
       i
       
       =
       
       1; 
       
       i
       
       <=
       
       n; 
       
       i
       
       ++)
       
       
    {
       
       
        
       
       if(
       
       dp[
       
       i] 
       
       > 
       
       max)
       
       
        {
       
       
            
       
       l 
       
       = 
       
       i;
       
       
            
       
       max 
       
       = 
       
       dp[
       
       i];
       
       
        }
       
       
    }
       
       
    
       
       printf(
       
       "%d\n",
       
       max);
       
       
    
       
       output(
       
       l);
       
       
    
       
       return 
       
       0;
       
       
}
      
      
      
      

       
       
1.
       
       
2.
       
       
3.
       
       
4.
       
       
5.
       
       
6.
       
       
7.
       
       
8.
       
       
9.
       
       
10.
       
       
11.
       
       
12.
       
       
13.
       
       
14.
       
       
15.
       
       
16.
       
       
17.
       
       
18.
       
       
19.
       
       
20.
       
       
21.
       
       
22.
       
       
23.
       
       
24.
       
       
25.
       
       
26.
       
       
27.
       
       
28.
       
       
29.
       
       
30.
       
       
31.
       
       
32.
       
       
33.
       
       
34.
       
       
35.
       
       
36.
       
       
37.
       
       
38.
       
       
39.
       
       
40.
       
       
41.
       
       
42.
       
       
43.
       
       
44.
       
       
45.
       
       
46.
       
       
47.
       
       
48.
       
       
49.
       
       
50.
       
       
51.
       
       
52.
       
       
53.
       
       
54.
       
       
55.
       
       
56.
       
       
57.
       
       
58.
       
       
59.
       
       
60.
       
       
61.
       
       
62.
       
       
63.
       
       
64.
       
       
65.
       
       
66.
       
       
67.
       
       
68.