'commit'

TangDou/Topic/HuanGenDp/P1364_dfs.cpp

@@ -0,0 +1,51 @@
+#include <bits/stdc++.h>
+using namespace std;
+const int N = 110, M = N << 1;
+const int INF = 0x3f3f3f3f;
+int n;
+int x[N];      // 点权权值数组
+int st[N];     // st 数组存是否遍历过这个节点
+int dis[N][N]; // 存节点间的距离
+
+// 链式前向星
+int e[M], h[N], idx, w[M], ne[M];
+void add(int a, int b, int c = 0) {
+    e[idx] = b, ne[idx] = h[a], w[idx] = c, h[a] = idx++;
+}
+
+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
+    st[u] = 1;                                // u走过了，防止回头路
+    dis[root][u] = step, dis[u][root] = step; // root<->u之间的路径长度
+
+    for (int i = h[u]; ~i; i = ne[i]) {
+        int v = e[i];
+        if (st[v]) continue;
+        dfs(root, v, step + 1);
+    }
+}
+
+int main() {
+    // 初始化链式前向星
+    memset(h, -1, sizeof h);
+
+    cin >> n;
+    for (int i = 1; i <= n; i++) {
+        int a, b;
+        cin >> x[i] >> a >> b;
+        if (a) add(i, a), add(a, i); // 存图
+        if (b) add(i, b), add(b, i);
+    }
+    for (int i = 1; i <= n; i++) {
+        memset(st, 0, sizeof st);
+        dfs(i, i, 0); // 搜索
+    }
+    int ans = INF;
+    for (int i = 1; i <= n; i++) {
+        int s = 0;
+        for (int j = 1; j <= n; j++)
+            s = s + x[j] * dis[i][j]; // 累加距离
+        ans = min(ans, s);
+    }
+    cout << ans << endl;
+    return 0;
+}