FZU 2082 过路费(树链剖分）

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FZU 2082 过路费

题目链接

树链抛分修改边的模板题

代码：

#include <cstdio>#include <cstring>#include <vector>using namespace std;typedef long long ll;const int N = 50005;int dep[N], id[N], sz[N], top[N], son[N], fa[N], idx;int n, m;ll bit[N];struct Edge {int u, v;ll val;void read() {scanf("%d%d%lld", &u, &v, &val);}} e[N];vector<int> g[N];inline int lowbit(int x) {return x&(-x);}void dfs1(int u, int f, int d) {dep[u] = d;sz[u] = 1;fa[u] = f;son[u] = 0;for (int i = 0; i < g[u].size(); i++) {int v = g[u][i];if (v == f) continue;dfs1(v, u, d + 1);sz[u] += sz[v];if (sz[son[u]] < sz[v])son[u] = v;}}void dfs2(int u, int tp) {top[u] = tp;id[u] = idx++;if (son[u]) dfs2(son[u], tp);for (int i = 0; i < g[u].size(); i++) {int v = g[u][i];if (v == fa[u] || v == son[u]) continue;dfs2(v, v);}}void add(int x, ll v) {while (x < N) {bit[x] += v;x += lowbit(x);}}ll query(int x) {ll ans = 0;while (x) {ans += bit[x];x -= lowbit(x);}return ans;}ll query(int l, int r) {return query(r) - query(l - 1);}ll gao(int u, int v) {int tp1 = top[u], tp2 = top[v];ll ans = 0;while (tp1 != tp2) {if (dep[tp1] < dep[tp2]) {swap(tp1, tp2);swap(u, v);}ans += query(id[tp1], id[u]);u = fa[tp1];tp1 = top[u];}if (u == v) return ans;if (dep[u] > dep[v]) swap(u, v);ans += query(id[son[u]], id[v]);return ans;}int main() {while (~scanf("%d%d", &n, &m)) {idx = 0;memset(bit, 0, sizeof(bit));for (int i = 1; i <= n; i++) g[i].clear();for (int i = 1; i < n; i++) {e[i].read();g[e[i].u].push_back(e[i].v);g[e[i].v].push_back(e[i].u);}dfs1(1, 0, 1);dfs2(1, 1);for (int i = 1; i < n; i++) {if (dep[e[i].u] < dep[e[i].v]) swap(e[i].u, e[i].v);add(id[e[i].u], e[i].val);}int ty, a, b;while (m--) {scanf("%d%d%d", &ty, &a, &b);if (ty == 0) {ll tmp = query(id[e[a].u], id[e[a].u]);add(id[e[a].u], (ll)b - tmp);} else printf("%lld\n", gao(a, b));}}return 0;}

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