SDUT2013级测试赛_D

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
struct node
{
    int v,next;
} edge[100000];
int head[10010],cnt,vv[10010],vis[10010],n,maxx;
void add(int u,int v)
{
    edge[cnt].v=v;
    edge[cnt].next=head[u];
    head[u]=cnt++;
}
void dfs(int s,int d)
{
    int i,j;
    for(i=head[s]; i!=-1; i=edge[i].next)
        dfs(edge[i].v,d+vv[edge[i].v]);
    if(d>maxx)
        maxx=d;
}
int main()
{
    int i,j,v,w;
    while(~scanf("%d",&n))
    {
        maxx=0;
        cnt=0;
        memset(edge,0,sizeof(edge));
        memset(vv,0,sizeof(vv));
        memset(head,-1,sizeof(head));
        for(i=0; i<n; i++)
        {
            scanf("%d%d",&v,&w);
            add(v-1,i);
            vv[i]=w;
        }
        dfs(0,vv[0]);
        printf("%d\n",maxx);
    }
    return 0;
}

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <queue>
#include <cmath>
#include <stack>
#include <map>

#pragma comment(linker, "/STACK:1024000000");
#define EPS (1e-8)
#define LL long long
#define ULL unsigned long long
#define _LL __int64
#define _INF 0x3f3f3f3f
#define Mod 9999991

using namespace std;

int head[10010];

struct E
{
    int v,next;
}edge[10010];

int Top;

int Link(int u,int v)
{
    edge[Top].v = v;
    edge[Top].next = head[u];
    head[u] = Top++;
}

int value[10010];

int dfs(int root)
{
    int temp = 0;

    for(int p = head[root];p != -1; p = edge[p].next)
    {
        temp = max(temp,dfs(edge[p].v));
    }

    value[root] += temp;

    return value[root];
}

int main()
{
    freopen("data1.in","r",stdin);
    freopen("data1.out","w",stdout);
    int n,i,j,v,w;

    while(scanf("%d",&n) != EOF)
    {
        memset(head,-1,sizeof(head));
        Top = 0;

        for(i = 1;i <= n; ++i)
        {
            scanf("%d %d",&v,&w);
            Link(v,i);
            value[i] = w;
        }

        printf("%d\n",dfs(1));
    }
    return 0;
}