luoguP2173 [ZJOI2012]网络 LCT

链接

luogu

思路

颜色很少，开10个lct分别维护

if (Hash.count(make_pair(u, v)) && Hash[make_pair(u, v)] == col) {puts("Success.");continue;}

这一行的代码调了半天。

代码

#include <bits/stdc++.h>
#define ls c[x][0]
#define rs c[x][1]
using namespace std;
const int N = 5e4 + 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;        
}
map<pair<int, int>, int> Hash;
int n, m, c, k, w[N];
struct LCT {
    int ru[N];
    int f[N], c[N][2], ma[N], stak[N], lazy[N];
    bool isroot(int x) {return c[f[x]][0] == x || c[f[x]][1] == x;}
    void pushup(int x) {ma[x] = max(max(ma[ls], ma[rs]), w[x]);}
    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);
        }
    }
}lct[11];
int main() {
    // freopen("a.in", "r", stdin);
    int n = read(), m = read(), c = read(), k = read();
    for (int i = 1; i <= n; ++i) w[i] = read();
    for (int i = 1; i <= m; ++i) {
        int u = read(), v = read(), col = read();
        Hash[make_pair(u, v)] = col;
        Hash[make_pair(v, u)] = col;
        lct[col].link(u, v);
        lct[col].ru[u]++,lct[col].ru[v]++;
    }
    for (int i = 1; i <= k; ++i) {
        int opt = read();
        if (opt == 0) {
            int x = read(), y = read();
            w[x] = y;
            for (int j = 0; j <= c; ++j) 
                lct[j].splay(x),lct[j].pushup(x);
        } else if (opt == 1) {
            int u = read(), v = read(), col = read();
            if (Hash.count(make_pair(u, v)) && Hash[make_pair(u, v)] == col) {puts("Success.");continue;}
            if (!Hash.count(make_pair(u, v))) {puts("No such edge.");continue;}
            if (lct[col].ru[u] >= 2 || lct[col].ru[v] >= 2) {puts("Error 1.");continue;}
            if (lct[col].findroot(u) == lct[col].findroot(v)) {puts("Error 2.");continue;}
            int old_col = Hash[make_pair(u,v)];
            Hash[make_pair(u, v)] = Hash[make_pair(v, u)] = col;
            lct[old_col].ru[u]--, lct[old_col].ru[v]--;
            lct[col].ru[u]++, lct[col].ru[v]++;
            lct[old_col].cut(u, v);
            lct[col].link(u, v);
            puts("Success.");
        } else {
            int col = read(), u = read(), v = read();
            if (lct[col].findroot(u) == lct[col].findroot(v)) {
                lct[col].split(u, v);
                printf("%d\n", lct[col].ma[v]);
            } else puts("-1");
        }
    }
    return 0;
}