bzoj 1146 网络管理Network (CDQ 整体二分 + 树刨）

#include<bits/stdc++.h>
using namespace std;
#define Fop freopen("_in.txt","r",stdin); freopen("_out.txt","w",stdout);
#define LL long long
#define ULL unsigned LL
#define fi first
#define se second
#define pb push_back
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define lch(x) tr[x].son[0]
#define rch(x) tr[x].son[1]
#define max3(a,b,c) max(a,max(b,c))
#define min3(a,b,c) min(a,min(b,c))
typedef pair<int,int> pll;
const int inf = 0x3f3f3f3f;
const int _inf = 0xc0c0c0c0;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const LL _INF = 0xc0c0c0c0c0c0c0c0;
const LL mod =  (int)1e9+7;
const int N = 8e5 + 100;
const int M = 2 * N;
int head[N], to[M], nt[M];
int sz[N], son[N], deep[N], top[N], fa[N], dfn[N], dto[N], tr[N<<2];
int tot, dtot;
int n;
int a[N];
struct Node{
    int k, a, b, id;
}A[M], B[M], C[M];
/**
k == -1 Add -> pos[a] = b
k == -2 Del -> pos[a] = 0
else k Query with ans[id]
**/
void add(int u, int v){
    to[tot] = v; nt[tot] = head[u]; head[u] = tot++;

    to[tot] = u; nt[tot] = head[v]; head[v] = tot++;
}
void dfs1(int o, int u){
    sz[u] = 1;
    for(int i = head[u]; ~i; i = nt[i]){
        int v = to[i];
        if(v == o) continue;
        dfs1(u, v);
        if(sz[v] > sz[son[u]]) son[u] = v;
        sz[u] += sz[v];
    }
}
void dfs2(int o, int u, int t){
    deep[u] = deep[o] + 1;
    top[u] = t;
    fa[u] = o;
    dfn[u] = ++dtot;
    dto[dtot] = u;
    if(son[u]) dfs2(u, son[u], t);
    for(int i = head[u]; ~i; i = nt[i]){
        int v = to[i];
        if(v == o || v == son[u]) continue;
        dfs2(u, v, v);
    }
}
void PushUp(int rt){
    tr[rt] = tr[rt<<1] + tr[rt<<1|1];
}
int Query(int L, int R, int l, int r, int rt){
    if(L <= l && r <= R)
        return tr[rt];
    int m = l+r >> 1;
    int ret = 0;
    if(L <= m) ret += Query(L, R, lson);
    if(m < R) ret += Query(L, R, rson);
    return ret;
}
void Updata(int L, int C, int l, int r, int rt){
    if(l == r){
        tr[rt] = C;
        return ;
    }
    int m = l+r >> 1;
    if(L <= m) Updata(L, C, lson);
    else Updata(L, C, rson);
    PushUp(rt);
    return ;
}
int Query_Path(int x, int y){
    int fx = top[x], fy = top[y];
    int ret = 0;
    while(fx != fy){
        if(deep[fx] > deep[fy]){
            ret += Query(dfn[fx],dfn[x],1,n,1);
            x = fa[fx]; fx = top[x];
        }
        else {
            ret += Query(dfn[fy],dfn[y],1,n,1);
            y = fa[fy]; fy = top[y];
        }
    }
    if(deep[x] < deep[y]) ret += Query(dfn[x], dfn[y], 1, n, 1);
    else ret += Query(dfn[y], dfn[x], 1, n,1);
    return ret;
}
int lca(int x, int y){
    int fx = top[x], fy = top[y];
    while(fx != fy){
        if(deep[fx] > deep[fy])
            x = fa[fx]; fx = top[x];
        else
            y = fa[fy]; fy = top[y];
    }
    if(deep[x] < deep[y]) return x;
    return y;
}
void init(){
    memset(head, -1, sizeof(head));
    memset(son, 0, sizeof son);
    tot = dtot = 0;
}
int atot = 0;
void AddNode(int op, int a, int b, int id){
    A[++atot] = {op, a, b, id};
}
int ans[N];
void cdq(int ansl, int ansr, int l, int r){
    if(l > r) return ;
    if(ansl == ansr){
        for(int i = l; i <= r; ++i)
            if(A[i].id)
                ans[A[i].id] = ansl;
        return ;
    }
    int mid = ansl+ansr >> 1;
    int tb = 0, tc = 0;
    for(int i = l; i <= r; ++i){
        if(A[i].k == -1){
            if(A[i].b <= mid){
                B[++tb] = A[i];
                Updata(dfn[A[i].a], 1, 1, n, 1);
            }
            else {
                C[++tc] = A[i];
            }
        }
        else if(A[i].k == -2){
            if(A[i].b <= mid){
                B[++tb] = A[i];
                Updata(dfn[A[i].a], 0, 1, n, 1);
            }
            else
                C[++tc] = A[i];
        }
        else {
            int kk = Query_Path(A[i].a, A[i].b);
            if(kk >= A[i].k)
                B[++tb] = A[i];
            else
                A[i].k -= kk;
                C[++tc] = A[i];
        }
    }
    for(int i = 1; i <= tb; ++i)
        A[i+l-1] = B[i];
    for(int i = 1; i <= tc; ++i)
        A[tb+l+i-1] = C[i];
    cdq(ansl, mid, l, tb+l-1);
    cdq(mid+1, ansr, tb+l, r);
}
int main(){
    init();
    int q;
    scanf("%d%d", &n, &q);
    for(int i = 1; i <= n; ++i) {
        scanf("%d", &a[i]);
        AddNode(-1, i, a[i], 0);
    }
    int x, y;
    for(int i = 1; i < n; ++i) {
        scanf("%d%d", &x, &y);
        add(x, y);
    }
    int m = 0;
    dfs1(1,1);
    dfs2(1,1,1);
    int k;
    for(int i = 1; i <= q; ++i){
        scanf("%d%d%d", &k, &x, &y);
        if(k) {
            int z = lca(x,y);
            z = deep[x] + deep[y] - deep[z] * 2 + 1;
            if(z < k){
                ans[++m] = -1;
            }
            else AddNode(z-k+1, x, y, ++m);
        }
        else {
            AddNode(-2, x, a[x], 0);
            AddNode(-1, x, y, 0);
            a[x] = y;
        }
    }
    for(int i = 1; i <= n; ++i)
        AddNode(-2, i, a[i], 0)
    cdq(1, 1e8+10, 1, atot);
    for(int i = 1; i <= m; ++i)
        if(~ans[i]) printf("%d\n", ans[i]);
        else puts("invalid request!");
    return 0;
}