#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);}
}