为什么我的程序限时错误?
因为排序?
这是问题
link text
#include <cstdio>
#include <cstring>
using namespace std;
int map[22][44];
int book[22];
int total;
int sum;
int way[22];
int tails[22];
int tail;
void init()
{
memset(map,0,sizeof(map));
memset(book,0,sizeof(book));
sum =0;
memset(way,0,sizeof(way));
way[1]=1;
memset(tails,0,sizeof(tails));
}
void sort()
{
int t;
for (int i=1;i<=22;i++)
{
if (tails[i]==0)
break;
else
{
for (int j=1;j<=tails[i]-1;j++)
for (int k=j+1;k<=tails[i];k++)
{
if (map[i][j] > map[i][k])
{
t = map[i][j];
map[i][j]=map[i][k];
map[i][k]=t;
}
}
}
}
}
void dfs(int x,int y)
{
if ((x < 1)||(x > 22))
return;
if (book[x]==1)
return;
//printf("%d \n",x);
if (x == total)
{
sum++;
for (int i=1;i<=y-1;i++)
{
printf("%d ",way[i]);
}
printf("%d",total);
printf("\n");
return;
}
tail = tails[x];
for (int i=1;i<=43;i++)
{
book[x]=1;
way[y]=x;
dfs(map[x][i],y+1);
book[x]=0;
}
}
int main()
{
int temp1,temp2;
//freopen("ex.in","r",stdin);
//freopen("ex.out","w",stdout);
int c = 0;
while(scanf("%d",&total)!=EOF)
{
c++;
printf("CASE ");
printf("%d",c);
printf(":");
printf("\n");
init();
for (;;)
{
scanf("%d%d",&temp1,&temp2);
if ((temp1 == 0)&&(temp2 == 0))
break;
else
{
tails[temp1]++;
tail = tails[temp1];
map[temp1][tail]=temp2;
tails[temp2]++;
tail = tails[temp2];
map[temp2][tail]=temp1;
}
}
sort();
dfs(1,1);
printf("There are ");printf("%d",sum);printf(" routes from the firestation to streetcorner ");printf("%d",total);printf(".");
printf("\n");
}
return 0;
}
最佳答案
因为您的排序算法为最坏情况O(n * n),所以您可以使用InnoSort获得更好的最坏情况复杂度O(n*log(n))
。
您正在使用C ++,然后使用sort
标头中的<algorithm>
函数来做到这一点最简单。
您可以在http://www.sgi.com/tech/stl/sort.html上找到的文档
关于c++ - uvaoj 208我如何加快我的程序,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/3178928/