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#include <bits/stdc++.h>
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using namespace std;
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const int N = 110, M = N << 1;
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const int INF = 0x3f3f3f3f;
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int n;
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int x[N]; // 点权权值数组
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int st[N]; // st 数组存是否遍历过这个节点
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int dis[N][N]; // 存节点间的距离
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// 链式前向星
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int e[M], h[N], idx, w[M], ne[M];
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void add(int a, int b, int c = 0) {
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e[idx] = b, ne[idx] = h[a], w[idx] = c, h[a] = idx++;
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}
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void dfs(int root, int u, int step) { // root 表示根,u:当前走到哪个节点，step:到u点时走了几步
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st[u] = 1; // u走过了，防止回头路
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dis[root][u] = step, dis[u][root] = step; // root<->u之间的路径长度
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for (int i = h[u]; ~i; i = ne[i]) {
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int v = e[i];
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if (st[v]) continue;
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dfs(root, v, step + 1);
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}
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}
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int main() {
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// 初始化链式前向星
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memset(h, -1, sizeof h);
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cin >> n;
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for (int i = 1; i <= n; i++) {
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int a, b;
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cin >> x[i] >> a >> b;
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if (a) add(i, a), add(a, i); // 存图
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if (b) add(i, b), add(b, i);
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}
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for (int i = 1; i <= n; i++) {
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memset(st, 0, sizeof st);
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dfs(i, i, 0); // 搜索
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}
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int ans = INF;
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for (int i = 1; i <= n; i++) {
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int s = 0;
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for (int j = 1; j <= n; j++)
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s = s + x[j] * dis[i][j]; // 累加距离
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ans = min(ans, s);
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}
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cout << ans << endl;
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return 0;
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} |
