【SPOJ-QTREE】Query on a tree【Link-Cut Tree】

一开始写成成员函数，结果TLETLETLE了...

#include <cstdio>#include <algorithm>using namespace std;const int maxn = 25005, inf = 0x3f3f3f3f;int n, st[maxn], head[maxn], cnt;inline int iread() {int f = 1, x = 0; char ch = getchar();for(; ch < '0' || ch > '9'; ch = getchar()) f = ch == '-' ? -1 : 1;for(; ch >= '0' && ch <= '9'; ch = getchar()) x = x * 10 + ch - '0';return f * x;}struct _edge {int v, next;} g[maxn << 1];inline void add(int u, int v) {g[cnt] = (_edge) {v, head[u]};head[u] = cnt++;}int son[maxn][2], fa[maxn], w[maxn], __max[maxn];bool rev[maxn];inline bool isroot(int x) {return son[fa[x]][0] != x && son[fa[x]][1] != x;}inline void pushup(int x) {__max[x] = max(w[x], max(__max[son[x][0]], __max[son[x][1]]));}inline void pushdown(int x) {if(rev[x]) {rev[son[x][0]] ^= 1; rev[son[x][1]] ^= 1;swap(son[x][0], son[x][1]);rev[x] = 0;}}inline void maintain(int x) {int top = 0; st[++top] = x;for(; !isroot(x); x = fa[x]) st[++top] = fa[x];while(top) pushdown(st[top--]);}inline void rotate(int x) {int y = fa[x], z = fa[y], type = son[y][1] == x;fa[son[y][type] = son[x][!type]] = y;fa[x] = z;if(!isroot(y)) son[z][son[z][1] == y] = x;fa[son[x][!type] = y] = x;pushup(y); pushup(x);}inline void splay(int x) {maintain(x);while(!isroot(x)) {int y = fa[x], z = fa[y];if(isroot(y)) rotate(x);else if(son[z][0] == y ^ son[y][0] == x) rotate(x), rotate(x);else rotate(y), rotate(x);}}inline void access(int x) {for(int y = 0; x; y = x, x = fa[x]) {splay(x);son[x][1] = y;pushup(x);}}inline void makeroot(int x) {access(x); splay(x); rev[x] ^= 1;}inline void change(int x, int c) {splay(x); w[x] = c; pushup(x);}inline int query(int x, int y) {makeroot(x); access(y); splay(y); return __max[y];}int val[maxn];void dfs(int x, int f) {fa[x] = f;w[x] = __max[x] = val[x];for(int i = head[x]; ~i; i = g[i].next) if(g[i].v ^ f) dfs(g[i].v, x);}int main() {int T = iread();while(T--) {n = iread();for(int i = 0; i < maxn; i++)son[i][0] = son[i][1] = fa[i] = rev[i] = 0, head[i] = -1, w[i] = __max[i] = val[i] = -inf;cnt = 0;for(int i = 1; i < n; i++) {int x = iread(), y = iread(), c = iread();add(x, i + n); add(i + n, x); add(y, i + n); add(i + n, y);val[i + n] = c;}dfs(1, 0);while(1) {char ch = getchar(); for(; ch != 'Q' && ch != 'C' && ch != 'D'; ch = getchar());if(ch == 'D') break;int x = iread(), y = iread();if(ch == 'C') change(x + n, y);else if(ch == 'Q') printf("%d\n", query(x, y));}}return 0;}