poj 1192 最优联通子集 简单dp

    看起来和图相关，其实就是个简单dp，就和取最大连续和一样，只是在一颗树中取……

    有人说是树状dp，我也不知道是不是

/*author:jxylang:C/C++university:China,Xidian University**If you need to reprint,please indicate the source***/#include <iostream>#include <cstdio>#include <cstdlib>#include <vector>#include <cmath>#define INF 1E9using namespace std;vector<int> near[1001];int X[1001],Y[1001];int value[1001];int n,ans=-INF;int now[1001];int ok[1001];int dfs(int v){    ok[v]=1;    now[v]=value[v];    for(int i=0;i<near[v].size();i++)    {        int u=near[v][i];        if(ok[u])continue;        dfs(u);        now[v]+=(now[u]>0?now[u]:0);        ans=max(ans,now[v]);    }}int main(){    scanf("%d",&n);    int i,j;    for(i=0;i<n;i++)    {        scanf("%d%d%d",&X[i],&Y[i],&value[i]);    }    for(i=0;i<n;i++)    {        for(j=0;j<n;j++)        {            if(i==j)continue;            if(fabs(X[i]-X[j])+fabs(Y[i]-Y[j])>1)continue;            near[i].push_back(j);            near[j].push_back(i);        }    }    dfs(0);    printf("%d\n",ans);}