poj 1695 动态规划

思路：和黑书上的跳舞机类似

#include<map>

#include<set>

#include<cmath>

#include<queue>

#include<cstdio>

#include<vector>

#include<string>

#include<cstdlib>

#include<cstring>

#include<iostream>

#include<algorithm>

#define Maxn 31

#define Maxm 100010

#define LL __int64

#define Abs(x) ((x)>0?(x):(-x))

#define lson(x) (x<<1)

#define rson(x) (x<<1|1)

#define inf 0x7fffffff

#define Mod 1000000007

using namespace std;

int dp[Maxn][Maxn][Maxn][Maxn];

int dis[Maxn][Maxn];

int main()

{

    int t,n,i,j,x,k,r;

    scanf("%d",&t);

    while(t--){

        memset(dis,0,sizeof(dis));

        memset(dp,48,sizeof(dp));

        scanf("%d",&n);

        for(i=1;i<n;i++){

            for(j=i+1;j<=n;j++){

                scanf("%d",&x);

                dis[i][j]=dis[j][i]=x;

            }

        }

        memset(dp[1],0,sizeof(dp[1]));

        for(i=2;i<=n;i++){

            for(j=1;j<=i-1;j++){

                for(k=1;k<=i-1;k++){

                    for(r=1;r<=i-1;r++){

                        dp[i][i][k][r]=min(dp[i][i][k][r],dp[i-1][j][k][r]+dis[j][i]);

                        dp[i][j][i][r]=min(dp[i][j][i][r],dp[i-1][j][k][r]+dis[k][i]);

                        dp[i][j][k][i]=min(dp[i][j][k][i],dp[i-1][j][k][r]+dis[r][i]);

                    }

                }

            }

        }

        int ans=100000000;

        for(i=1;i<=n;i++){

            for(j=1;j<=n;j++){

                for(k=1;k<=n;k++){

                    ans=min(dp[n][i][j][k],ans);

                }

            }

        }

        printf("%d\n",ans);

    }

    return 0;

}