c语言noip试题,noip模拟题 收费站（cost）C/C++代码在某个遥远的国家里，有n个城市。编号为1，2，3，……，n，并有m条双向的公路。每条公路连接着两个城市。开车每经过一个城市，都会被收...

#include //记录每一步的选择。

struct SearchStep

{

int city;

int road;

int s;

SearchStep* next;

SearchStep* pre;

};

struct Road

{

int startc;

int endc;

int ci;

};

int FindNextCity(SearchStep* as,Road* ar,int n)

{

//查找线路是否有一端符合当前城市

int icity;

SearchStep* ps;

if (ar->startc == n)

icity = ar->endc ;

else if (ar->endc == n)

icity = ar->startc ;

else

return 0;

//查找线路是否已经过另一端城市

ps = as;

while (ps != NULL)

{

if (ps->city == icity)

return 0;

ps = ps->next ;

}

return icity;

}

int DoSearch(SearchStep* as,int aa,Road* ar,int* ac,int* ap,int ad)

{

//as 搜寻的路径；

//aa 公路数，ar 公路信息

//ac 最低的最高线路途经城市费用

//ap 城市收费信息

//ad 目标城市

int m,nextcity,nexts,ipay,imax;

SearchStep *ps,*pp;

ps = as;

if (ps->city == ad)

{

//查找所经过的路径，设置最大缴费值，比较缴费值和起讫城市的收费值，如果和其中之一相等，则直接返回

pp = ps;

while (pp != NULL)

{

ipay = *(ap + pp->city -1);

if (imax < ipay)

imax = ipay;

pp = pp->pre ;

}

*ac = imax;

if ((imax == *(ap + as->city -1)) || (imax == *(ap + ps->city -1)))

return 1;

else

{

if (ps->pre != NULL)

{

ps = ps->pre ;

ps ->next = NULL;

}

return 0;

}

}

m = ps->road;

while (m < aa)

{

nextcity = FindNextCity(as,ar + m,ps->city);

if (nextcity > 0)

{

//执行到下一步

if (*ac > 0)

if (*(ap + nextcity -1) > *ac)

{

//如果所到城市的费用大于已有线路最大费用，跳过

m++;

continue;

}

if (ps->s - (ar + m)->ci > 0)

{

ps->next = new SearchStep;

ps->road = m;

ps = ps->next;

ps->next =NULL;

ps->pre =as;

ps->city = nextcity;

ps->road = 0;

ps->s = as->s - (ar + m)->ci;

nexts = DoSearch(ps,aa,ar,ac,ap,ad);

if (nexts == 1) return nexts;

}

}

m++;

}

if (ps->pre != NULL)

{

ps = ps->pre ;

ps ->next = NULL;

}

return 0;

}

int main(int argc, char* argv[])

{

//第一步，录入城市数量，线路数量，出发城市，目标城市，汽车油箱容量

int ccount,rcount,startc,endc,vehs,imaxcost;

int inputright;

inputright = 0;

while (inputright == 0)

{

cout << "请输入城市数量，线路数量，出发城市，目标城市，汽车油箱容量\n";

cin >> ccount >> rcount >> startc >> endc >> vehs;

if (startc > ccount || endc > ccount)

cout << "出发城市或目标城市不能大于城市数，请重新输入！";

else if (ccount > 10000)

cout << "城市数量不能大于10000，请重新输入！";

else if (rcount > 50000)

cout << "线路数量不能大于50000，请重新输入！";

else

inputright ++;

}

//初始化城市收费，线路信息

int *Pcity = new int [ccount];

Road *Proad = new Road [rcount];

int i,num1,num2,num3;

srand((unsigned)time(NULL));

for (i = 0;i {

num1 = rand()%10000 + 1;

*(Pcity + i) = num1;

}

for (i = 0; i {

num1 = rand()%ccount + 1;

num2 = rand()%ccount + 1;

if (num1 == num2)

{

num2 = (num1 + 1) % ccount + 1;

}

(Proad + i)->startc = num1;

(Proad + i)->endc = num2;

num3 = rand()%10000 + 1;

(Proad + i)->ci = num3;

}

//输出题目的数据

cout << "城市数量\t线路数量\t出发城市\t目标城市\t汽车油箱容量\n";

cout << ccount << "\t" << rcount << "\t" ;

cout << startc << "\t" << endc << "\t" ;

cout << vehs << "\n";

for (i = 0;i cout << *(Pcity + i) << "\n";

for (i = 0;i cout << (Proad + i)->startc << "\t"<< (Proad + i)->endc << "\t"

// getchar();

//开始寻找线路

SearchStep sFirst;

sFirst.next = NULL;

sFirst.city = startc;

sFirst.pre = NULL;

sFirst.road = 0;

sFirst.s = vehs;

imaxcost = -1;

DoSearch(&sFirst,rcount,Proad,&imaxcost,Pcity,endc);

//输出结果

cout << "搜索结果为：" << imaxcost << endl;

getchar();

return 0;

}