求AOE网络中的关键路径算法

//求AOE网络中的关键路径算法
#include <cstdio>
#include <cstring>
#define MAXN 100 //顶点个数的最大值
#define MAXM 200 //边数的最大值
struct ArcNode
{
int to, dur, no; //边的另一个顶点，持续时间，活动序号
ArcNode *next;
};
int n, m; //顶点个数、边数
ArcNode* List1[MAXN]; //每个顶点的边链表表头指针(出边表) ArcNode* List2[MAXN]; //每个顶点的边链表表头指针(入边表) int count1[MAXN]; //各顶点的入度
int count2[MAXN]; //各顶点的出度
int Ee[MAXN]; //各事件的最早可能开始时间
int El[MAXN]; //各事件的最迟允许开始时间
int e[MAXM]; //各活动的最早可能开始时间
int L[MAXM]; //各活动的最迟允许开始时间
void CriticalPath( ) //求关键路径
{
//拓扑排序求Ee
int i, j, k;
int top1 = -1;
ArcNode* temp1;
memset( Ee, 0, sizeof(Ee) );
for( i=0; i<n; i++ )
{
if( count1[i]==0 )
count1[i] = top1, top1 = i;
}
for( i=0; i<n; i++ )
{
if( top1==-1 )
{
printf( "Network has a cycle!\n" ); return;
}
else
{
j = top1; top1 = count1[top1];
temp1 = List1[j];
while( temp1!=NULL )
{
k = temp1->to;
if( --count1[k]==0 )
count1[k] = top1, top1 = k;
if( Ee[j] + temp1->dur > Ee[k] ) //有向边<j,k> Ee[k] = Ee[j] + temp1->dur;
temp1 = temp1->next;
}//end of while
}//end of else
}//end of for
//逆拓扑排序求El
int top2 = -1;
ArcNode* temp2;
for( i=0; i<n; i++ )
{
El[i] = Ee[n-1];
if( count2[i]==0 )
count2[i] = top2, top2 = i;
}
for( i=0; i<n; i++ )
{
j = top2; top2 = count2[top2];
temp2 = List2[j];
while( temp2!=NULL )
{
k = temp2->to;
if( --count2[k]==0 )
count2[k] = top2, top2 = k;
if( El[j] - temp2->dur < El[k] ) //有向边<k,j> El[k] = El[j] - temp2->dur;
temp2 = temp2->next;
}//end of while
}//end of for
//求各活动的e[k]和L[k]
memset( e, 0, sizeof(e) ); memset( L, 0, sizeof(L) ); printf( "The critical activities are:\n" );
for( i=0; i<n; i++ ) //释放边链表上各边结点所占用的存储空间{
temp1 = List1[i];;
while( temp1!=NULL )
j = temp1->to; k=temp1->no; //有向边<i,j>
e[k] = Ee[i]; L[k] = El[j] - temp1->dur;
if( e[k]==L[k] )
printf( "A%d : %d->%d\n", k, i, j );
temp1 = temp1->next;
}
}
}
int main( )
{
int i, u, v, w; //循环变量、边的起点和终点
scanf( "%d%d", &n, &m ); //读入顶点个数n，边数
memset( List1, 0, sizeof(List1) ); memset( List2, 0, sizeof(List2) );
memset( count1, 0, sizeof(count1) ); memset( count2, 0, sizeof(count2) );
ArcNode *temp1, *temp2;
for( i=0; i<m; i++ )
{
scanf( "%d%d%d", &u, &v, &w ); //读入边的起点和终点
count1[v]++;
temp1 = new ArcNode; //构造邻接表
temp1->to = v; temp1->dur = w;
temp1->no = i+1; temp1->next = NULL;
if( List1[u]==NULL ) List1[u] = temp1;
else{ temp1->next = List1[u]; List1[u] = temp1; }
count2[u]++;
temp2 = new ArcNode; //构造邻接表
temp2->to = u; temp2->dur = w;
temp2->no = i+1; temp2->next = NULL;
if( List2[v]==NULL ) List2[v] = temp2;
else{ temp2->next = List2[v]; List2[v] = temp2; } }
CriticalPath( );
for( i=0; i<n; i++ ) //释放边链表上各边结点所占用的存储空间
{
temp1 = List1[i]; temp2 = List2[i];
while( temp1!=NULL )
{
List1[i] = temp1->next; delete temp1; temp1 = List1[i];
}
while( temp2!=NULL )
List2[i] = temp2->next; delete temp2; temp2 = List2[i];
}
}
return 0;
}
代码来自。