> 类似的题目，我总是用回溯，结果总是 TLE，请教高手，应该怎么做。
> 
> #include "iostream.h"
> 
> #define max 6
> 
> int graph[max];
> int map[max];
> int total;		//总和，加权后
> 
> bool check()
> {
> 	int i;
> 	int t = 0;
> 	for( i = 0 ; i < max ; i++ )
> 		t += ( i + 1 ) * map[i];
> 	if( t == total / 2 )
> 		return true;
> 	else
> 		return false;
> }
> 
> int main()
> {
> 	int i;
> 	int sum;		//个数
> 	bool flag;
> 	int top;
> 	int caseCount = 0;
> 	
> 	sum = 0;
> 	total = 0;
> 	for( i = 0 ; i < max ; i++ )
> 	{
> 		cin >> graph[i];
> 		sum += graph[i];
> 		total += ( i + 1 ) * graph[i];
> 	}
> 	while( sum > 0 )
> 	{
> 		caseCount++;
> 		cout<<"Collection #"<<caseCount<<":"<<endl;
> 		if( total % 2 == 0 )
> 		{
> 			for( i = 0 ; i < max ; i++ )
> 				map[i] = -1;
> 			top = 0;
> 			flag = false;//没有找到分法
> 			do
> 			{
> 				map[top]++;
> 				if( map[top] > graph[top] )
> 				{
> 					map[top] = -1;
> 					top--;
> 				}
> 				else
> 				{
> 					if( top == max - 1 )
> 					{
> 						if( check() )
> 						{
> 							cout<<"Can be divided."<<endl;
> 							flag = true;
> 						}
> 					}
> 					else
> 					{
> 						top++;
> 					}
> 				}
> 			}while( top >= 0 && !flag );
> 			if( !flag )
> 				cout<<"Can't be divided."<<endl;
> 		}		
> 		else
> 		{
> 			cout<<"Can't be divided."<<endl;
> 		}
> 		cout<<endl;
> 		//==================================
> 		//下一循环
> 		sum = 0;
> 		total = 0;
> 		for( i = 0 ; i < max ; i++ )
> 		{
> 			cin >> graph[i];
> 			sum += graph[i];
> 			total += ( i + 1 ) * graph[i];
> 		}
> 	}
> 	
> 	return 0;
> }