[BZOJ 1207][HNOI2004]打鼹鼠：DP

/*
User:Small
Language:C++
Problem No.:1207
*/
#include<bits/stdc++.h>
#define ll long long
#define inf 999999999
using namespace std;
const int M=1e4+5;
int f[M],n,m,mx[M],x[M],y[M],t[M],ans;
int main(){
freopen("data.in","r",stdin);//
scanf("%d%d",&n,&m);
for(int i=1;i<=m;i++){
scanf("%d%d%d",&t[i],&x[i],&y[i]);
f[i]=1;
for(int j=i-1;j;j--){
if(mx[j]+1<=f[i]) break;
if(f[j]+1>f[i]&&abs(x[i]-x[j])+abs(y[i]-y[j])<=t[i]-t[j]) f[i]=f[j]+1;
}
mx[i]=max(mx[i-1],f[i]);
ans=max(ans,f[i]);
}
printf("%d\n",ans);
return 0;
}