UVA 437 - The Tower of Babylon （DAG）

#include <cstdio>
#include <algorithm>
#include <iostream>
#include <string>
#include <map>
#include <vector>
#include <set>
#include <cmath>
#include <stack>
#include <queue>
#include <cstring>
#define ll long long;
#define maxn 1000 + 10
#define INF 100000000
using namespace std;
struct ti{
    int x,y,z;
    void f(int a,int b,int c){x = a, y = b, z = c;}
};
ti s[maxn * 6];
int g[maxn * 6][maxn * 6];
int dp[maxn * 6];
int num;
int solve(int i,int j){
    if((s[i].x < s[j].x && s[i].y < s[j].y ))
        return 1;
    return 0;
}
int dfs(int u) {
    if(dp[u] != -1) return dp[u];
    dp[u] = s[u].z;
    for(int i = 0; i < num; ++i) if(g[u][i]){
        dp[u] = max(dp[u], dfs(i)+s[u].z);
    }
    return dp[u];
}
int main (){
    int n;
    int counts = 0;
    while(scanf("%d",&n) && n){
        memset(dp,-1,sizeof(dp));
        num = 0;
        for(int i = 0 ; i < n ;i++){
            int a,b,c;
            scanf("%d%d%d",&a,&b,&c);
            s[num++].f(a,b,c);
            s[num++].f(a,c,b);
            s[num++].f(b,a,c);
            s[num++].f(b,c,a);
            s[num++].f(c,a,b);
            s[num++].f(c,b,a);
        }
        for(int i = 0 ; i < num ; i++){
            for(int j = i+1 ; j < num ; j++){
                g[i][j] = solve(i,j);
                g[j][i] = solve(j,i);
            }
        }
        int he = -1;
        for(int i = 0 ; i < num ; i++){
            dp[i] = dfs(i);
            he = max(he,dp[i]);
        }
        printf("Case %d: maximum height = %d\n",++counts,he);
    }
    return 0;
}