路由最佳路径选择

有N个路由器，路由A到路由B的延迟是time, 可以表示为 {A->B,time},不联通的路由延迟用-1表示，设计一个算法，求两个路由最小延迟的路径。

#include<iostream> 
#include <string>
#include <vector>
using namespace std;

// 路由器个数
#define ROUTER_COUNTS  20

typedef struct
{
	int nSrc;  //起点
	int nDst;  //终点
	int nTime; //耗时秒

}POS_USE_TIME; //两点用时

typedef struct
{
	int    code;    //代号(下标)
	string strName; //路由名称

} ROUTER_Def;

//初始化路由器
void InitRt(vector< ROUTER_Def> &routerVec)
{
	int nSize = routerVec.size();
	if (nSize == 0)
	{
		for (int i = 0; i < ROUTER_COUNTS; i++)
		{
			ROUTER_Def router;
			router.code = i;
			char str[30] = { 0 };
			sprintf(str, "router-%d", i);
			router.strName = string(str);
			routerVec.push_back(router);
		}
	}
	else
	{
		for (int i = 0; i < nSize; i++)
		{
			routerVec[i].code = i;
			char str[30] = { 0 };
			sprintf(str, "router-%d", i);
			routerVec[i].strName = string(str);
		}
	}
	
}

/*************
  功能：设置路由联通耗时
  返回：N*N数组
//************/
int** InitTime(vector< POS_USE_TIME>& tmVec, vector< ROUTER_Def>& routerVec)
{
	int nSize  = routerVec.size();
	int** ptr = new int*[nSize];
	for (int i = 0; i < nSize; i++)
	{
		ptr[i] = new int[nSize];
	}

	for (int i = 0; i < nSize; i++)
	for (int j = 0; j < nSize; j++)
	{
		POS_USE_TIME usetime;
		usetime.nSrc  = i;
		usetime.nDst  = j;
		usetime.nTime =  -1; // 当i==j表示同一个路由器，同一路由器不存在联通关系 
		
			//******设定联通路径，验证是否被找出****** 
	
		//例 1 ：0->3->7->8->18
		if ((i == 0 && j == 3) || (i == 3 && j == 7) || (i == 7 && j == 8) || (i == 8 && j == 18))
			usetime.nTime = 1;
		
		//例 2 ：0->5->6->9->18
		if ((i == 0 && j == 5) || (i == 5 && j == 6) || (i == 6 && j == 9) || (i == 9 && j == 18))
			usetime.nTime = 2;

			//************/

		ptr[i][j] = usetime.nTime;
		tmVec.push_back(usetime);
	}
	return ptr;
}

// 在N*N数组中查找出联通的所有路径
int SearchPath(int**pArray,int nSrc,int nDst,int nSize, vector< vector<int>>& linkVec, vector<int> &itemsVec)
{
	//越界
	if (nSrc > nSize || nSrc < 0 
		|| nDst > nSize || nDst < 0) return -1;

	//同一路由
	if (nSrc == nDst) return -1;

	
	for (int i = 0; i < nSize; i++)
	{
		// 不联通
		if ( pArray[nSrc][i] == -1) continue;
		itemsVec.push_back(i);
		if (i == nDst)//达到目标
		{
			linkVec.push_back(itemsVec);
			return 0;
		}
		else
		{
			SearchPath(pArray,  i,  nDst,  nSize, linkVec, itemsVec);
			itemsVec.pop_back();
		}

	}
	return -1;
}

//最短路径
void MinPath(int** pArray,vector< vector<int>> linkVec, vector< ROUTER_Def> routerVec)
{
	int nSize = linkVec.size();
	if (nSize == 0)
	{
		cout << "null" << endl;
		return;
	}

	int nPath = -1, nIndex = 0;
	for (int i = 0; i < nSize; i++)
	{
		int nValue = 0;
		int nItemSize = linkVec[i].size();
		int nPx = linkVec[i][0];
		for (int j=1;j<nItemSize;j++)
		{
			int nPy = linkVec[i][j];
			nValue += pArray[nPx][nPy];
			nPx = nPy;
		}
		if (nPath == -1)
		{
			nPath = nValue;
			nIndex = i;
		}
		else if (nValue < nPath)
		{
			nPath = nValue;
			nIndex = i;
		}
	}
	cout << "最短距离：" << nPath <<" 具体如下："<< endl;

	//打印
	int nItemSize = linkVec[nIndex].size();
	for (int j = 0; j < nItemSize; j++)
	{
		cout << routerVec[linkVec[nIndex][j]].strName;
		if (j < (nItemSize - 1))
		{
			cout << " -> ";
		}
		else cout << endl;
	}

}

void FindGoodPath(int nSrc, int nDst)
{
	vector< ROUTER_Def> routerVec;
	vector< POS_USE_TIME> tmVec;
	InitRt(routerVec);
	int**pArray = InitTime(tmVec, routerVec);
	int nSize = routerVec.size();

	vector< vector<int>> linkVec;
	vector<int> itemsVec;

	if(nSrc>=0 && nSrc<nSize) itemsVec.push_back(nSrc);

	SearchPath(pArray, nSrc, nDst, nSize, linkVec, itemsVec);

	//计算具体路径并打印结果
	MinPath(pArray, linkVec, routerVec);
}

int main()
{
	int nStart = 0, nEnd = 3;
	while (cin >> nStart >> nEnd)
	{
		FindGoodPath(nStart, nEnd);
	}
	return 0;
}