bzoj3531: [Sdoi2014]旅行 （树链剖分 && 动态开点线段树）

感觉动态开点线段树空间复杂度好优秀呀

树剖裸题

把每个宗教都开一颗线段树就可以了

但是我一直TLE

然后调了一个小时

为什么呢

因为我 #define max(x, y) (x > y ? x : y)

看起来好像可以减少常数的样子

我也是这么想的（作死

事实上

ans = max(ans, query(x, y))

类似这种语句中

query(x, y)会计算两次

然后就GG了

这告诉我们还是好好用库里的函数吧

 #include <cstdio>
 #include <algorithm>
 #include <vector>
 using namespace std;
 const int N =  + ;
 const int M =  + ;
 #define isdigit(x) (x >= '0' && x <= '9')

 inline void read(int &ans) {
     ans = ;
     static char buf = getchar();
     register int res = ;
     for (; !isdigit(buf); buf = getchar())
         if (buf == '-') res = -;
     for (; isdigit(buf); buf = getchar())
         ans = ans *  + buf - '';
     ans *= res;
 }

 int tot, n, q;
 int sz[N], hs[N], pos[N], fa[N], top[N], w[N], c[N], dep[N];
 vector < int > E[N];

 void dfs1(int x, int d, int f) {
     dep[x] = d; fa[x] = f;
     hs[x] = -; sz[x] = ;
     int tmp = ;
     for (int i = ; i < E[x].size(); i++) {
         int u = E[x][i];
         if (u == f) continue;
         dfs1(u, d + , x);
         sz[x] += sz[u];
         if (tmp < sz[u])
             tmp = sz[u], hs[x] = u;
     }
 }

 void dfs2(int x, int t) {
     top[x] = t; pos[x] = ++tot;
     if (hs[x] == -)    return;
     dfs2(hs[x], t);
     for (int i = ; i < E[x].size(); i++)
         if (E[x][i] != fa[x] && E[x][i] != hs[x])
             dfs2(E[x][i], E[x][i]);
 }

 int cnt;
 int sum[M], maxn[M], ls[M], rs[M], root[N];

 inline void pushUp(int o) {
     maxn[o] = max(maxn[ls[o]], maxn[rs[o]]);
     sum[o] = sum[ls[o]] + sum[rs[o]];
 }

 void modify(int &o, int l, int r, int p, int c) {
     if (!o) o = ++cnt;
     if (l == r) {
         sum[o] = maxn[o] = c;
         return ;
     }
     int mid = l + r >> ;
     if (p <= mid)    modify(ls[o], l, mid, p, c);
     else    modify(rs[o], mid + , r, p, c);
     pushUp(o);
 }

 int querySum(int o, int l, int r, int L, int R) {
     if (!o) return ;
     if (l >= L && r <= R) return sum[o];
     int mid = l + r >> , ans = ;
     if (L <= mid)    ans += querySum(ls[o], l, mid, L, R);
     if (R > mid) ans += querySum(rs[o], mid + , r, L, R);
     return ans;
 }

 inline int querySum(int c, int x, int y) {
     int f1 = top[x], f2 = top[y];
     int ans = ;
     while (f1 != f2) {
         if (dep[f1] < dep[f2])
             swap(x, y), swap(f1, f2);
         ans += querySum(root[c], , n, pos[f1], pos[x]);
         x = fa[f1]; f1 = top[x];
     }
     if (dep[x] > dep[y]) swap(x, y);
     ans += querySum(root[c], , n, pos[x], pos[y]);
     return ans;
 }

 int queryMax(int o, int l, int r, int L, int R) {
     if (!o) return ;
     if (l >= L && r <= R) return maxn[o];
     int mid = l + r >> , ans = ;
     if (L <= mid)    ans = max(ans, queryMax(ls[o], l, mid, L, R));
     if (R > mid) ans = max(ans, queryMax(rs[o], mid + , r, L, R));
     return ans;
 }

 inline int queryMax(int c, int x, int y) {
     int f1 = top[x], f2 = top[y];
     int ans = ;
     while (f1 != f2) {
         if (dep[f1] < dep[f2])
             swap(x, y), swap(f1, f2);
         ans = max(ans, queryMax(root[c], , n, pos[f1], pos[x]));
         x = fa[f1]; f1 = top[x];
     }
     if (dep[x] > dep[y]) swap(x, y);
     ans = max(ans, queryMax(root[c], , n, pos[x], pos[y]));
     return ans;
 }

 int main() {
     read(n); read(q);
     for (int i = ; i <= n; i++)
         read(w[i]), read(c[i]);
     for (int i = ; i < n; i++) {
         int u, v;
         read(u); read(v);
         E[u].push_back(v);
         E[v].push_back(u);
     }
     dfs1(, , ); dfs2(, );
     for (int i = ; i <= n; i++)
         modify(root[c[i]], , n, pos[i], w[i]);
     for (int i = ; i <= q; i++) {
         char ch[]; scanf("%s", ch);
         int x, y; read(x); read(y);
         if (ch[] == 'C') {
             if (ch[] == 'C') {
                 modify(root[c[x]], , n, pos[x], );
                 c[x] = y;
                 modify(root[y], , n, pos[x], w[x]);
             }
             else {
                 modify(root[c[x]], , n, pos[x], y);
                 w[x] = y;
             }
         }
         else {
             if (ch[] == 'S')
                 printf("%d\n", querySum(c[x], x, y));
             else    printf("%d\n", queryMax(c[x], x, y));
         }
     }
     return ;
 }