其实本题非常的无脑,无脑拍完1A,写到blog里只因为TM无脑拍也拍了很久啊= =
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <climits>
#include <string>
#include <iostream>
#include <map>
#include <cstdlib>
#include <list>
#include <set>
#include <queue>
#include <stack>
#include <sstream>using namespace std;typedef long long LL;
const int maxn = 2000;
const int maxm = 2000 * 2000;
const double INF = 1e30;
const double eps = 1e-7;
struct Point {double x,y;Point(double x = 0,double y = 0):x(x),y(y) {}
};Point str(0,5),end(10,5);
vector<Point> p,pw;
double dist[maxn][maxn],d[maxn];
int N,M;int dcmp(double x) {if(fabs(x) < eps) return 0;if(x < 0) return -1;return 1;
}Point operator - (Point a,Point b) {return Point(a.x - b.x,a.y - b.y);
}double Cross(Point a,Point b) {return a.x * b.y - a.y * b.x;
}double Dot(Point a,Point b) {return a.x * b.x + a.y * b.y;
}bool SegmentCross(Point a1,Point a2,Point b1,Point b2) {double c1 = Cross(a2 - a1,b1 - a1),c2 = Cross(a2 - a1,b2 - a1),c3 = Cross(b2 - b1,a1 - b1),c4 = Cross(b2 - b1,a2 - b1);return dcmp(c1) * dcmp(c2) < 0 && dcmp(c3) * dcmp(c4) < 0;
}bool nonecross(Point a1,Point a2) {for(int i = 0;i < pw.size();i += 2) {if(SegmentCross(a1,a2,pw[i],pw[i + 1]))return false;}return true;
}void solve() {//构建邻接矩阵M = p.size();for(int i = 0;i < M;i++) {for(int j = i + 1;j < M;j++) {if(nonecross(p[i],p[j])) {dist[i][j] = dist[j][i] = sqrt(Dot(p[i]-p[j],p[i]-p[j]));} else dist[i][j] = INF;}}//bellman-fordfor(int i = 0;i < M;i++) d[i] = INF;d[0] = 0;for(int i = 0;i < M;i++) {for(int j = 0;j < M;j++) {for(int k = 0;k < M;k++) if(dist[j][k] < INF) {if(d[j] < INF) {d[k] = min(d[k],d[j] + dist[j][k]);}}}}printf("%.2f\n",d[M - 1]);
}int main() {while(cin >> N,N != -1) {p.clear();pw.clear();p.push_back(Point(0,5));for(int i = 1;i <= N;i++) {double posx,posy;cin >> posx;pw.push_back(Point(posx,0));for(int j = 0;j < 4;j++) {cin >> posy;p.push_back(Point(posx,posy));pw.push_back(Point(posx,posy));}pw.push_back(Point(posx,10));}p.push_back(Point(10,5));solve();}return 0;
}