[NOI2014]魔法森林
链接
思路
a排序，b做动态最小生成树。
把边拆成点就可以了。
uoj98.也许lct复杂度写假了、、越卡常，越慢
代码
#include <bits/stdc++.h>
#define ls c[x][0]
#define rs c[x][1]
using namespace std;
const int N = 2e5 + 7;
int read() {
int x = 0, f = 1; char s = getchar();
for (;s > '9' || s < '0'; s = getchar()) if (s == '-') f = -1;
for (;s >= '0' && s <= '9'; s = getchar()) x = x * 10 + s - '0';
return x * f;
}
struct edge {
int x, y, a, b;
bool operator < (const edge &zz) const {
return (a^zz.a) ? a < zz.a : b < zz.b;
}
} G[N];
int f[N], c[N][2], w[N][2], ma[N][2], stak[N], lazy[N], id[N];
bool isroot(int x) {return c[f[x]][0] == x || c[f[x]][1] == x;}
void pushup(int x) {
ma[x][0] = max(max(ma[ls][0], ma[rs][0]), w[x][0]);
ma[x][1] = max(max(ma[ls][1], ma[rs][1]), w[x][1]);
id[x] = (ma[x][1] == w[x][1]) ? x : (ma[ls][1] > ma[rs][1]) ? id[ls] : id[rs];
}
void tag(int x){swap(ls,rs), lazy[x] ^= 1;}
void pushdown(int x) {
if (lazy[x]) {
if (ls) tag(ls);
if (rs) tag(rs);
lazy[x] ^= 1;
}
}
void rotate(int x) {
int y = f[x], z = f[y], k = c[y][1] == x, w = c[x][!k];
if (isroot(y)) c[z][c[z][1] == y] = x;
c[x][!k] = y, c[y][k] = w;
if (w) f[w] = y;
f[x] = z, f[y] = x;
pushup(y);
}
void splay(int x) {
int y = x, z = 0;
stak[++z] = y;
while (isroot(y)) stak[++z] = y = f[y];
while (z) pushdown(stak[z--]);
while (isroot(x)) {
y = f[x], z = f[y];
if (isroot(y)) rotate((c[y][0] == x)^(c[z][0] == y) ? x : y);
rotate(x);
}
pushup(x);
}
void access(int x) {
for (int y = 0; x;x = f[y = x])
splay(x), rs = y, pushup(x);
}
void makeroot(int x) {
access(x), splay(x);
tag(x);
}
int findroot(int x) {
access(x), splay(x);
while(ls) pushdown(x), x = ls;
return x;
}
void split(int x, int y) {
makeroot(x), access(y), splay(y);
}
void link(int x, int y) {
makeroot(x);
if (findroot(y) != x) f[x] = y;
}
void cut(int x, int y) {
makeroot(x);
if (findroot(y) == x && f[x] == y && !rs) {
f[x] = c[y][0] = 0;
pushup(y);
}
}
int main() {
int n = read(), m = read(), ans = 0x3f3f3f3f;
for (int i = 1; i <= m; ++i)
G[i].x = read(), G[i].y = read(), G[i].a = read(), G[i].b = read();
sort(G + 1, G + 1 + m);
for (int i = 1; i <= m; ++i) {
if (G[i].x == G[i].y) continue;
int x = G[i].x, y = G[i].y;
if (findroot(x) == findroot(y)) {
split(x, y);
if (ma[y][1] > G[i].b) {
int tmp = id[y];
cut(G[tmp - n].x, tmp), cut(G[tmp - n].y, tmp);
w[n + i][0] = G[i].a, w[n + i][1] = G[i].b;
link(x, n + i), link(n + i, y);
}
} else {
w[n + i][0] = G[i].a, w[n + i][1] = G[i].b;
link(x, n + i), link(n + i, y);
}
if (findroot(1) == findroot(n)) {
split(1, n);
ans = min(ans, ma[n][0] + ma[n][1]);
}
}
printf("%d\n", ans == 0x3f3f3f3f ? -1 : ans);
return 0;
}