Links : http://acm.hdu.edu.cn/showproblem.php?pid=1069
The meaning of problems : n kinds of rectangular block, dimensions x, y, z, according to the length and width requirements stacked strictly decreasing (not equal), can be folded up to ask how high
Thinking : due to one of three pieces of wood stacked manner, the one kind of wood to be copied into three candidate set is added, let long x, y is the width, z is high, the problem turned into a wood taken the decline sequence x, y is also declined sequence, and z, and the largest, linked to fat mice that question this is the bare question, ah , give x ordering, x is the drop sequence, then this sequence of seeking y the longest decline sequences. The longest decline sequences can refer to this topic
Code :
1 #include<bits/stdc++.h> 2 // #include<iostream> 3 // #include<cstdio> 4 // #include<cmath> 5 #define inf 0x3f3f3f3f 6 using namespace std; 7 8 typedef long long ll; 9 typedef long double ld; 10 11 const int M = int(1e5)*3 + 5; 12 const int mod = 10056; 13 14 inline int lowbit(int x) { 15 return x & (-x); 16 } 17 18 struct node{ 19 ll x,y,z; 20 }; 21 vector<node> v; 22 23 int n,kase; 24 ll ans; 25 ll dp[M]; 26 27 void add(int& x,int& y,int& z){ 28 if(x>y) swap(x,y); 29 if(y>z) swap(y,z); 30 if(x>y) swap(x,y); 31 v.push_back({z,y,x}); 32 v.push_back({z,x,y}); 33 v.push_back({y,x,z}); 34 } 35 bool cmp(node a,node b){ 36 return a.x==b.x?a.y>b.y:a.x>b.x; 37 } 38 int main(){ 39 while(cin>>n && n){ 40 ans=0; 41 v.clear(); 42 43 while(n--){ 44 int x,y,z; 45 cin>>x>>y>>z; 46 add(x,y,z); 47 } 48 49 sort(v.begin(),v.end(),cmp); 50 // printf(" x y z \n"); 51 // for(auto x:v) printf("%3d %3d %3d\n",x.x,x.y,x.z); 52 53 int N=v.size(); 54 for(int i=0;i<N;i++) dp[i]=v[i].z; 55 56 for(int i=0;i<N;i++){ 57 // printf("%d:%d %d %d\n",i,v[i].x,v[i].y,v[i].z); 58 for(int j=i-1;j>=0;j--){ 59 // printf("\t%d:%d %d %d",j,v[j].x,v[j].y,v[j].z); 60 if(v[i].x<v[j].x && v[i].y<v[j].y){ 61 dp[i]=max(dp[i],dp[j]+v[i].z); 62 } 63 // printf(" %d\n",dp[j]); 64 } 65 } 66 67 for(int i=0;i<N;i++){ 68 ans=max(ans,dp[i]); 69 } 70 71 printf("Case %d: maximum height = %d\n",++kase,ans); 72 } 73 return 0; 74 }
Note : the difficulty is one kind of think there are three pieces of wood pendulum method, I think six pendulum method