Description
These days, Busoniya want to hold a large-scale theatrical performance in this stadium. There will be N people go there numbered 1--N. Busoniya has Reserved several seats. To make it funny, he makes M requests for these seats: A B X, which means people numbered B must seat clockwise X distance from people numbered A. For example: A is in column 4th and X is 2, then B must in column 6th (6=4+2).
Now your task is to judge weather the request is correct or not. The rule of your judgement is easy: when a new request has conflicts against the foregoing ones then we define it as incorrect, otherwise it is correct. Please find out all the incorrect requests and count them as R.
Input
For every case:
The first line has two integer N(1<=N<=50,000), M(0<=M<=100,000),separated by a space.
Then M lines follow, each line has 3 integer A(1<=A<=N), B(1<=B<=N), X(0<=X<300) (A!=B), separated by a space.
Output
Output R, represents the number of incorrect request.
Sample Input
Sample Output
Hint
#include<stdio.h>
const int N=50005;
int d[N],seat[N];
int n,count;
int find(int x)
{
if(x==d[x]) return x;
int t=d[x];
d[x]=find(d[x]);
seat[x]+=seat[t]; //seat表示點的位置
return d[x];
}
void merge(int x,int y,int z)
{
int fx=find(x);
int fy=find(y);
if(fx!=fy)
{
seat[fy]=seat[x]+z+seat[fy]-seat[y]; //
d[fy]=fx;
}
else if(seat[y]!=seat[x]+z)
count++;
}
int main()
{
int a,b,c,m;
while(~scanf("%d%d",&n,&m))
{
count=0;
for(int i=1;i<=n;i++)
{
d[i]=i;
seat[i]=0;
}
while(m--)
{
scanf("%d%d%d",&a,&b,&c);
merge(a,b,c);
}
printf("%d\n",count);
}
}