UOJ #274. 【清华集训2016】温暖会指引我们前行 [lct]

#274. 【清华集训2016】温暖会指引我们前行

题意比较巧妙

裸lct维护最大生成树

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
typedef long long ll;
#define lc t[x].ch[0]
#define rc t[x].ch[1]
#define pa t[x].fa
const int N = 4e5+5, INF = 1e9+5;
inline int read(){
	char c=getchar(); int x=0,f=1;
	while(c<'0' || c>'9') {if(c=='-')f=-1; c=getchar();}
	while(c>='0' && c<='9') {x=x*10+c-'0'; c=getchar();}
	return x*f;
}

int n, m, val[N], id, u, v, tem, w;
struct edge{int u, v;} e[N];
char s[10];

namespace lct {
	struct meow{ int ch[2], fa, rev, sum, w, p; } t[N];
	inline int wh(int x) {return t[pa].ch[1] == x;}
	inline bool isr(int x) {return t[pa].ch[0] != x && t[pa].ch[1] != x;}
	inline void rever(int x) {t[x].rev ^= 1; swap(lc, rc);}
	inline void pushdn(int x) {
		if(t[x].rev) {
			if(lc) rever(lc);
			if(rc) rever(rc);
			t[x].rev = 0;
		}
	}
	inline void pd(int x) {if(!isr(x)) pd(pa); pushdn(x);}
	inline void update(int x) {
		t[x].sum = t[lc].sum + t[rc].sum + t[x].w;
		t[x].p = x;
		if(lc && val[ t[lc].p ] < val[ t[x].p ]) t[x].p = t[lc].p;
		if(rc && val[ t[rc].p ] < val[ t[x].p ]) t[x].p = t[rc].p;
	}
	inline void rotate(int x) {
		int f = t[x].fa, g = t[f].fa, c = wh(x);
		if(!isr(f)) t[g].ch[wh(f)] = x; t[x].fa = g;
		t[f].ch[c] = t[x].ch[c^1]; t[ t[f].ch[c] ].fa = f;
		t[x].ch[c^1] = f; t[f].fa = x;
		update(f); update(x);
	}
	inline void splay(int x) {
		pd(x);
		for(; !isr(x); rotate(x))
			if(!isr(pa)) rotate(wh(x) == wh(pa) ? pa : x);
	}
	inline void access(int x) {
		for(int y=0; x; y=x, x=pa)
			splay(x), rc=y, update(x);
	}
	inline void maker(int x) { access(x); splay(x); rever(x);}
	inline void link(int x, int y) { maker(x); t[x].fa = y; }
	inline void cut(int x, int y) {
		maker(x); access(y); splay(y);
		t[x].fa = t[y].ch[0] = 0; update(y);
	}
	inline void split(int x, int y) { maker(x), access(y); splay(y); }
} using namespace lct;

int fa[N];
inline int find(int x) {return x == fa[x] ? x : fa[x] = find(fa[x]);}
inline void add() {
	id=read()+1+n, u=read()+1, v=read()+1, tem=read(), w=read(); //printf("\nadd %d  %d--%d  %d  %d\n", id, u, v, tem, w);
	e[id] = (edge){u, v};
	val[id] = tem;
	t[id].sum = t[id].w = w; t[id].p = id;
	if(find(u) != find(v)) {
		fa[find(u)] = find(v);
		link(id, u); link(id, v);
	} else {
		split(u, v);
		int a = t[v].p; //printf("aaa %d\n", a);
		if(val[a] < val[id]) {
			cut(a, e[a].u); cut(a, e[a].v);
			link(id, u); link(id, v);
		}
	}
}
inline void que(int u, int v) {
	if(find(u) != find(v)) puts("-1");
	else split(u, v), printf("%d\n", t[v].sum);
}
inline void cha(int id, int w) { //printf("\ncha %d  %d\n", id, w);
	t[id].w = w; splay(id);
}
int main() {
	freopen("in", "r", stdin);
	n=read(); m=read();
	for(int i=1; i<=n; i++) fa[i] = i, val[i] = INF;
	for(int i=1; i<=m; i++) { //printf("\nQ %d\n", i);
		scanf("%s", s);
		if(s[0] == 'f') add();
		if(s[0] == 'm') u=read()+1, v=read()+1, que(u, v);
		if(s[0] == 'c') id=read()+1+n, w=read(), cha(id, w);
	}
}