VJ - dp - Monkey and Banana - 最长单调序列

Posted 2021-03-13 popodynasty

https://vjudge.net/contest/353156#problem/A

一开始想着按背包做 = = 

我的dp还是太菜了

应该按照单调序列做

 1 #include <iostream>
 2 #include <algorithm>
 3 #include <vector>
 4 using namespace std;
 5 struct node{
 6     int l;
 7     int s;
 8     int v;
 9     int ans;
10     node(){
11         ans = 0;
12     }
13 };
14 inline node newone(int a,int b,int c){
15     node New;
16     New.l = max(a,b);
17     New.s = min(a,b);
18     New.v = c;
19     New.ans = New.v;
20     return New;
21 }
22 void init(vector<node>& vec,int n){
23     int a,b,c;
24     for(int i = 0; i < n; i++){
25         cin >> a >> b >> c;
26         vec.push_back(newone(a,b,c));
27         vec.push_back(newone(a,c,b));
28         vec.push_back(newone(c,b,a));
29     }
30 }
31 
32 bool comp(const node&a,const node&b){
33     if(a.l != b.l)return a.l > b.l;
34     else return a.s > b.s;
35 }
36 int main(){
37     int cnt = 1;
38     int n;
39     while(cin >> n && n){
40         vector<node> vec;
41         init(vec,n);
42         sort(vec.begin(),vec.end(),comp);
43         int s = 3 * n - 1;
44         for(int i = s-1; i >= 0; i--){
45             for(int j = i+1; j <= s; j++){
46                 if(vec[i].l > vec[j].l && vec[i].s > vec[j].s)
47                     vec[i].ans = max(vec[i].ans,vec[j].ans + vec[i].v);
48             }
49         }
50         
51         int ans = 0;
52         for(int i = 0; i <= s; i++)
53             ans = max(ans,vec[i].ans);
54         cout<<"Case "<<cnt++<<": maximum height = "<<ans<<endl;
55     }
56     return 0;
57 }