zoukankan      html  css  js  c++  java
  • POJ 2677 Tour

    双调欧几里得 DP



    Tour
    Time Limit: 1000MS   Memory Limit: 65536K
    Total Submissions: 3581   Accepted: 1596

    Description

    John Doe, a skilled pilot, enjoys traveling. While on vacation, he rents a small plane and starts visiting beautiful places. To save money, John must determine the shortest closed tour that connects his destinations. Each destination is represented by a point in the plane pi = < xi,yi >. John uses the following strategy: he starts from the leftmost point, then he goes strictly left to right to the rightmost point, and then he goes strictly right back to the starting point. It is known that the points have distinct x-coordinates. 
    Write a program that, given a set of n points in the plane, computes the shortest closed tour that connects the points according to John's strategy.

    Input

    The program input is from a text file. Each data set in the file stands for a particular set of points. For each set of points the data set contains the number of points, and the point coordinates in ascending order of the x coordinate. White spaces can occur freely in input. The input data are correct.

    Output

    For each set of data, your program should print the result to the standard output from the beginning of a line. The tour length, a floating-point number with two fractional digits, represents the result. An input/output sample is in the table below. Here there are two data sets. The first one contains 3 points specified by their x and y coordinates. The second point, for example, has the x coordinate 2, and the y coordinate 3. The result for each data set is the tour length, (6.47 for the first data set in the given example).

    Sample Input

    3
    1 1
    2 3
    3 1
    4
    1 1
    2 3
    3 1
    4 2

    Sample Output

    6.47
    7.89

    Source

    [Submit]   [Go Back]   [Status]   [Discuss]


    #include <iostream>
    #include <cstdio>
    #include <cstring>
    #include <algorithm>
    #include <cmath>
    
    using namespace std;
    
    double x[100],y[100];
    
    double dist(int a,int b)
    {
    	return sqrt((x[a]-x[b])*(x[a]-x[b])+(y[a]-y[b])*(y[a]-y[b]));
    }
    
    double dp[100][100];
    int n;
    
    int main()
    {
    	while(cin>>n)
    	{
    		for(int i=1;i<=n;i++)
    		{
    			cin>>x[i]>>y[i];
    		}
    		for(int i=0;i<=n;i++)
    		{
    			for(int j=0;j<=n;j++)
    			{
    				dp[i][j]=99999999;
    			}
    		}
    		dp[1][1]=0; dp[2][1]=dist(1,2);
    		for(int i=1;i<=n;i++)
    		{
    			for(int j=1;j<i;j++)
    			{
    				dp[i+1][j]=min(dp[i+1][j],dp[i][j]+dist(i+1,i));
    				dp[i+1][i]=min(dp[i+1][i],dp[i][j]+dist(i+1,j));
    			}
    		}
    		double ans=99999999;
    		for(int j=1;j<n;j++)
    			ans=min(ans,dp[n-1][j]+dist(j,n));
    		printf("%.2f
    ",ans+dist(n-1,n));
    	}
    	return 0;
    }




  • 相关阅读:
    深度学习之TensorFlow(一)——基本使用
    64位win10+cuda8.0+vs2013+cuDNN V5下Caffe的编译安装教程并配置matlab2014a 接口
    Win10+vs2012+cuda8.0的安装与配置
    图像处理与matlab实例之图像平滑(一)
    Windows下pycharm使用theano的方法
    Python中的支持向量机SVM的使用(有实例)
    混淆矩阵在Matlab中PRtools模式识别工具箱的应用
    模式识别与机器学习—bagging与boosting
    微服务架构下分布式事务解决方案——阿里GTS
    谈谈分布式事务
  • 原文地址:https://www.cnblogs.com/zfyouxi/p/4315545.html
Copyright © 2011-2022 走看看