156 lines
4.8 KiB
C++
156 lines
4.8 KiB
C++
#include<bits/stdc++.h>
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using namespace std;
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int n;
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vector<pair<int, int>> fri[200005];
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pair<int, int> edge[200005];
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int a[200005];
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int fa[200005];
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int dfn[200005];
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int nowdfn;
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int cnt[200005];
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int son[200005];
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int top[200005];
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int dep[200005];
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int m;
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struct SEG{
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int num[3][800005];
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bool lt[800005];
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void pu(int now, int op) {
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if(op == 0) num[op][now] = num[op][now * 2] + num[op][now * 2 + 1];
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else if(op == 1) num[op][now] = max(num[op][now * 2], num[op][now * 2 + 1]);
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else num[op][now] = min(num[op][now * 2], num[op][now * 2 + 1]);
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}
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void pu(int now) {pu(now, 0), pu(now, 1), pu(now, 2);}
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void dorev(int now) {
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lt[now] ^= 1;
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num[0][now] = -num[0][now];
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int tmp = num[1][now];
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num[1][now] = -num[2][now];
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num[2][now] = -tmp;
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}
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void pd(int now, int nl, int nr) {
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if(!lt[now]) return;
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dorev(now * 2);
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dorev(now * 2 + 1);
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lt[now] = 0;
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}
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void edit(int now, int nl, int nr, int l, int nn) {
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if(l < nl || l > nr) return;
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if(nl == nr) {
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num[0][now] = nn, num[1][now] = nn, num[2][now] = nn;
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return;
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}
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int nmid = (nl + nr) >> 1;
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pd(now, nl, nr);
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edit(now * 2, nl, nmid, l, nn);
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edit(now * 2 + 1, nmid + 1, nr, l, nn);
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pu(now);
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}
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void rev(int now, int nl, int nr, int l, int r) {
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if(nr < l || nl > r) return;
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if(l <= nl && nr <= r) {
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dorev(now);
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return;
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}
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pd(now, nl, nr);
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int nmid = (nl + nr) >> 1;
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rev(now * 2, nl, nmid, l, r);
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rev(now * 2 + 1, nmid + 1, nr, l, r);
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pu(now);
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}
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int query(int now, int nl, int nr, int l, int r, int op) {
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if(nr < l || nl > r) return (op==2)?INT_MAX:((op==1)?INT_MIN:0);
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if(l <= nl && nr <= r) {
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return num[op][now];
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}
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int nmid = (nl + nr) >> 1;
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pd(now, nl, nr);
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if(op == 0) return query(now * 2, nl, nmid, l, r, op) + query(now * 2 + 1, nmid + 1, nr, l, r, op);
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else if(op == 1) return max(query(now * 2, nl, nmid, l, r, op), query(now * 2 + 1, nmid + 1, nr, l, r, op));
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else return min(query(now * 2, nl, nmid, l, r, op), query(now * 2 + 1, nmid + 1, nr, l, r, op));
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}
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}seg;
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void dfs1(int now, int from) {
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cnt[now] = 1;
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for(pair<int, int> i : fri[now]) {
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if(i.second == from) continue;
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a[i.second] = i.first; // 边权转点权
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fa[i.second] = now;
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dep[i.second] = dep[now] + 1;
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dfs1(i.second, now);
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cnt[now] += cnt[i.second];
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if(cnt[i.second] > cnt[son[now]]) son[now] = i.second;
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}
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}
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void dfs2(int now, int from) {
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dfn[now] = ++nowdfn;
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seg.edit(1, 1, n, nowdfn, a[now]);
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top[now] = from;
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if(son[now]) dfs2(son[now], from);
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for(pair<int, int> i : fri[now]) {
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if(i.second == son[now] || i.second == fa[now]) continue;
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dfs2(i.second, i.second);
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}
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}
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void rev(int u, int v) {
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while(top[u] != top[v]) {
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if(dep[top[u]] < dep[top[v]]) swap(u, v);
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seg.rev(1, 1, n, dfn[top[u]], dfn[u]);
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u = fa[top[u]];
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}
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if(dep[u] < dep[v]) swap(u, v);
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if(dfn[v] + 1 <= dfn[u])
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seg.rev(1, 1, n, dfn[v] + 1, dfn[u]);
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}
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int f(int u, int v, int op) {
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int ans = 0;
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if(op == 1) ans = INT_MIN;
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if(op == 2) ans = INT_MAX;
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while(top[u] != top[v]) {
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if(dep[top[u]] < dep[top[v]]) swap(u, v);
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if(op == 0) ans += seg.query(1, 1, n, dfn[top[u]], dfn[u], 0);
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else if(op == 1) ans = max(ans, seg.query(1, 1, n, dfn[top[u]], dfn[u], 1));
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else ans = min(ans, seg.query(1, 1, n, dfn[top[u]], dfn[u], 2));
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u = fa[top[u]];
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}
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if(dep[u] < dep[v]) swap(u, v);
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if(dfn[v] + 1 <= dfn[u]) {
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if(op == 0) ans += seg.query(1, 1, n, dfn[v] + 1, dfn[u], 0);
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else if(op == 1) ans = max(ans, seg.query(1, 1, n, dfn[v] + 1, dfn[u], 1));
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else ans = min(ans, seg.query(1, 1, n, dfn[v] + 1, dfn[u], 2));
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}
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return ans;
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}
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int main() {
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scanf("%d", &n);
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for(int i = 1, u, v, w; i < n; ++i) {
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scanf("%d%d%d", &u, &v, &w);
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u++, v++;
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fri[u].push_back({w, v});
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fri[v].push_back({w, u});
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edge[i] = {u, v};
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}
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dfs1(1, 0);
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dfs2(1, 1);
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scanf("%d", &m);
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while(m--) {
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char op[5];
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int u, v;
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scanf("%s%d%d", op, &u, &v);
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if(op[0] == 'C') {
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pair<int, int> ed = edge[u];
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if(dep[ed.first] > dep[ed.second]) u = ed.first;
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else u = ed.second;
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seg.edit(1, 1, n, dfn[u], v);
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} else if(op[0] == 'N') {
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rev(u + 1, v + 1);
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} else if(op[0] == 'S') {
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printf("%d\n", f(u + 1, v + 1, 0));
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} else if(op[1] == 'A') {
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printf("%d\n", f(u + 1, v + 1, 1));
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} else {
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printf("%d\n", f(u + 1, v + 1, 2));
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}
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}
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return 0;
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} |