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85 lines
1.8 KiB
85 lines
1.8 KiB
#include <bits/stdc++.h>
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using namespace std;
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const int N = 100010, M = 200010;
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int depth[N], f[N][25];
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int n, m;
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int d[N];
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int ans;
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const int T = 17;
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int e[M], h[N], idx, ne[M];
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void add(int a, int b) {
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e[idx] = b, ne[idx] = h[a], h[a] = idx++;
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}
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int start = 1;
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void bfs() {
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queue<int> q;
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q.push(start);
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depth[start] = 1;
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while (q.size()) {
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int u = q.front();
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q.pop();
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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 (!depth[v]) {
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depth[v] = depth[u] + 1;
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q.push(v);
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f[v][0] = u;
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for (int k = 1; k <= T; k++) f[v][k] = f[f[v][k - 1]][k - 1];
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}
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}
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}
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}
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int lca(int a, int b) {
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if (depth[a] < depth[b]) swap(a, b);
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for (int i = T; i >= 0; i--)
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if (depth[f[a][i]] >= depth[b]) a = f[a][i];
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if (a == b) return a;
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for (int i = T; i >= 0; i--)
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if (f[a][i] != f[b][i])
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a = f[a][i], b = f[b][i];
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return f[a][0];
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}
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void dfs(int u, int fa) {
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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 (v == fa) continue;
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dfs(v, u);
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d[u] += d[v];
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}
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}
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int main() {
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int a, b;
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scanf("%d %d", &n, &m);
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memset(h, -1, sizeof h);
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for (int i = 1; i < n; i++) {
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scanf("%d %d", &a, &b);
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add(a, b), add(b, a);
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}
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bfs();
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for (int i = 0; i < m; i++) {
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scanf("%d %d", &a, &b);
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d[a]++, d[b]++;
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int p = lca(a, b);
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d[p] -= 2;
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}
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dfs(start, 0);
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for (int i = 1; i <= n; i++) {
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if (i == start) continue;
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if (d[i] == 0) ans += m;
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if (d[i] == 1) ans += 1;
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}
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printf("%d\n", ans);
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return 0;
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} |