FZU 2195 检查站点

求出根节点到每个叶子节点的距离，找到最大的。然后总权值减去最大叶子距离就是答案。

GNU C++ AC

Visual C++  TLE

#include<stdio.h>
#include<vector>
#include<map>
#include<algorithm>
using namespace std;

const int maxn = ;
vector<int> ljb[maxn];
int cost[maxn], ff;

void dfs(int node, int fahther, int tot)
{
    if (tot > ff) ff = tot;
    int i;
    for (i = ; i < ljb[node].size(); i++)
        dfs(ljb[node][i], node, tot + cost[ljb[node][i]]);
}
int main()
{
    int u, v, c, n, i;
    while (~scanf("%d", &n))
    {
        ff = ;
        for (i = ; i <= n; i++) ljb[i].clear();
        int summ = ;
        cost[] = ; ljb[].push_back();
        for (i = ; i < n - ; i++)
        {
            scanf("%d%d%d", &u, &v, &c);
            ljb[u].push_back(v);
            cost[v] = c;
            summ = summ + c;
        }
        dfs(, , );
        printf("%d\n", summ - ff);
    }
    return ;
}