题目链接

luoguP3302 [SDOI2013]森林

题解

本来这题树上主席树暴力启发式合并就完了

结果把lca写错了...

以后再也不这么写了

复杂度\(O(nlog^2n)\)

"for(int i = 0;dad[x][i];++ i) dad[x][i+1] = dad[dad[x][i]][i]"

De了两个多小时....QAQ

代码

#include<cstdio>

#include<cstring>

#include<algorithm> 

inline int read() {

    int x = 0,f = 1;

    char c = getchar();

    while(c < '0' || c > '9') {if(c == '-')f = -1;c = getchar(); }

    while(c <= '9' && c >= '0')x = x * 10 + c - '0',c = getchar();

    return x * f;

} 

const int maxn = 100007;

struct NNnode {

    int v,next;

} edge[maxn << 2];

int num = 0,head[maxn];

inline void add_edge(int u,int v)  {

    edge[++ num].v = v; edge[num].next = head[u]; head[u] = num;

} 

int root[maxn],val[maxn],n,m,t,MX;

int tot = 0;

int ls[40000000],rs[40000000],cnt[40000000];

void insert(int pre,int &now,int l,int r,int key) {

    cnt[++ tot] = cnt[now]; now = tot;

    ++ cnt[now];

    if(l == r) return ;

    int mid = l + r >> 1;

    ls[now] = ls[pre]; rs[now] = rs[pre];

    if(key <= mid) insert(ls[pre],ls[now],l,mid,key);

    else insert(rs[pre],rs[now],mid + 1,r,key);

} 

int query(int t1,int t2,int t3,int t4,int l,int r,int k) {

    if (l == r) return l;

    int mid = l + r >> 1;

    int dtl = cnt[ls[t1]] + cnt[ls[t2]] - cnt[ls[t3]] - cnt[ls[t4]];

    if(k <= dtl) return query(ls[t1],ls[t2],ls[t3],ls[t4],l,mid,k);

    else return query(rs[t1],rs[t2],rs[t3],rs[t4],mid + 1,r,k - dtl);

} 

int root_num[maxn],siz[maxn], dep[maxn],dad[maxn][25];

void dfs(int x) {

    siz[x] = 1;

    for(int i = 1;i < 20;++i)

      dad[x][i] = dad[dad[x][i - 1]][i - 1];

    insert(root[dad[x][0]],root[x],1,MX,val[x]);

    for(int i = head[x];i;i = edge[i].next) {

        int v = edge[i].v;

        if(v == dad[x][0]) continue;

        root_num[v] = root_num[x];

        dad[v][0] = x; dep[v] = dep[x] + 1;

        dfs(v);

        siz[x] += siz[v];

    }

}

int LCA(int x,int y) { 

    if(dep[x] > dep[y]) std::swap(x,y);

    for(int i = 19;i >= 0;i --) if(dep[dad[y][i]] >= dep[x]) y = dad[y][i];

    if(x == y) return x;

    for(int i = 19;i >= 0;i --) if(dad[y][i] != dad[x][i]) y = dad[y][i],x = dad[x][i];

    return dad[x][0];

}

int work_q(int x,int y,int k) {

    int lca = LCA(x,y);

    int F_lca = dad[lca][0];

    return query(root[x],root[y],root[lca],root[dad[lca][0]],1,MX,k);

}

void work_L(int x,int y) {

    //printf("%d ***** %d\n",x,y);

    if(siz[root_num[x]] < siz[root_num[y]]) std::swap(x,y);

    dad[y][0] = x;

    siz[root_num[x]] += siz[root_num[y]];

    root_num[y] = root_num[x];

    dep[y] = dep[x] + 1; add_edge(x,y);add_edge(y,x);

    dfs(y);

}

int b[maxn];

void solve() {

    tot = MX = 0;

    n = read(),m = read(); t = read();

    for(int i = 1;i <= n;++ i) b[i] = val[i] = read(),MX = std::max(val[i],MX);

    std::sort(b + 1,b + n + 1);

    int len = std::unique(b + 1,b + n + 1) - b - 1;

    for(int i = 1;i <= n;++ i) val[i] = std::lower_bound(b + 1,b + len + 1,val[i]) - b,MX = std::max(val[i],MX);

    for(int x,y,i = 1;i <= m;++ i) {

        x = read(), y = read();

        add_edge(x,y) , add_edge(y,x);

    }

    for(int i = 1;i <= n;++ i)

        if(!root_num[i]) root_num[i] = i,dep[i] = 1,dfs(i);

    char opt[20];

    int lans = 0;

    while(t --) {

        scanf("%s",opt + 1) ;

        if(opt[1] == 'Q')  {

            int x = read() ^ lans,y = read() ^ lans, k = read() ^ lans;

            //printf("%d **** %d *** %d *** &&&\n",x,y,lans);

            printf("%d\n",lans = b[work_q(x,y,k)]);

        } else {

            int x = read() ,y = read() ;

            x ^= lans,y ^= lans;

            //printf("%d **** %d *** %d *** ***\n",x,y,lans);

            work_L(x,y);

        }

    }

}

int main() {

    int testcase = read(); //whattttt the fucccck？

    testcase = 1;

    for(int i = 1;i <= testcase;++ i) solve();  

}