42 lines
905 B
C++
42 lines
905 B
C++
#include<iostream>
|
|
#include<cstdio>
|
|
#include<cmath>
|
|
#include<cstring>
|
|
#include<algorithm>
|
|
using namespace std;
|
|
const int M=10005;
|
|
int n,m;
|
|
struct node{
|
|
int t,x,y;
|
|
}E[M];
|
|
int dp[M];
|
|
int cmp(node n1,node n2){
|
|
return n1.t<n2.t;
|
|
}
|
|
int main()
|
|
{
|
|
int i,l;
|
|
int temp;
|
|
while(scanf("%d%d",&n,&m),n||m)
|
|
{
|
|
for(i=0;i<m;i++) scanf("%d%d%d",&E[i].t,&E[i].x,&E[i].y);
|
|
sort(E,E+m,cmp);
|
|
int ans;
|
|
ans=dp[0]=1;
|
|
for(i=1;i<m;i++)
|
|
{
|
|
dp[i]=0;
|
|
for(l=i-1;l>=0;l--)
|
|
{
|
|
temp=abs(E[i].x-E[l].x)+abs(E[i].y-E[l].y);
|
|
if(temp>E[i].t-E[l].t) continue;
|
|
dp[i]=dp[i]>(dp[l]+1)?dp[i]:(dp[l]+1);
|
|
}
|
|
if(!dp[i]) dp[i]=1;
|
|
if(dp[i]>ans) ans=dp[i];
|
|
}
|
|
cout<<ans<<endl;
|
|
}
|
|
return 0;
|
|
}
|