POJ 3237 Tree

POJ_3237

    用link-cut-tree或者树链剖分都可以，为了处理negate操作，出了lazy标记外可以做两个标记max、min，在执行negate时，令max=-min、min=-max即可。

#include<stdio.h>
#include<string.h>
#define MAXD 100010
#define MAXM 200010
#define INF 0x7fffffff
int N, q[MAXD], first[MAXD], e, next[MAXM], v[MAXM], w[MAXM], dep[MAXD];
struct Edge
{
    int x, y, z;
}edge[MAXD];
struct Splay
{
    int pre, ls, rs, neg, key, max, min;
    bool root;
    void update(); void pushdown(); void zig(int ); void zag(int ); void splay(int );
    void renew()
    {
        root = true;
        pre = ls = rs = 0;
        neg = 0;
    }
}sp[MAXD];
int Max(int x, int y)
{
    return x > y ? x : y;
}
int Min(int x, int y)
{
    return x < y ? x : y;
}
void Splay::update()
{
    max = Max(Max(sp[ls].max, sp[rs].max), key);
    min = Min(Min(sp[ls].min, sp[rs].min), key);
}
void makeneg(int cur)
{
    if(cur != 0)
    {
        sp[cur].neg ^= 1, sp[cur].key = -sp[cur].key;
        int t = sp[cur].max;
        sp[cur].max = -sp[cur].min, sp[cur].min = -t;
    }
}
void Splay::pushdown()
{
    if(neg)
    {
        makeneg(ls), makeneg(rs);
        neg = 0;
    }
}
void Splay::zig(int x)
{
    int y = rs, fa = pre;
    pushdown(), sp[y].pushdown();
    rs = sp[y].ls, sp[rs].pre = x;
    sp[y].ls = x, pre = y;
    sp[y].pre = fa;
    if(root)
        root = false, sp[y].root = true;
    else
        sp[fa].rs == x ? sp[fa].rs = y : sp[fa].ls = y;
    update();
}
void Splay::zag(int x)
{
    int y = ls, fa = pre;
    pushdown(), sp[y].pushdown();
    ls = sp[y].rs, sp[ls].pre = x;
    sp[y].rs = x, pre = y;
    sp[y].pre = fa;
    if(root)
        root = false, sp[y].root = true;
    else
        sp[fa].rs == x ? sp[fa].rs = y : sp[fa].ls = y;
    update();
}
void Splay::splay(int x)
{
    int y, z;
    for(pushdown(); !root;)
    {
        y = pre;
        if(sp[y].root)
            sp[y].rs == x ? sp[y].zig(y) : sp[y].zag(y);
        else
        {
            z = sp[y].pre;
            if(sp[z].rs == y)
            {
                if(sp[y].rs == x)
                    sp[z].zig(z), sp[y].zig(y);
                else
                    sp[y].zag(y), sp[z].zig(z);
            }
            else
            {
                if(sp[y].ls == x)
                    sp[z].zag(z), sp[y].zag(y);
                else
                    sp[y].zig(y), sp[z].zag(z);
            }
        }
    }
    update();
}
void add(int x, int y, int z)
{
    v[e] = y, w[e] = z;
    next[e] = first[x], first[x] = e ++;
}
void prepare()
{
    int i, j, x, rear = 0;
    sp[0].max = -INF, sp[0].min = INF;
    q[rear ++] = 1;
    sp[1].renew(), dep[1] = 1;
    for(i = 0; i < rear; i ++)
    {
        x = q[i];
        for(j = first[x]; j != -1; j = next[j])
            if(v[j] != sp[x].pre)
            {
                sp[v[j]].renew(), sp[v[j]].pre = x, dep[v[j]] = dep[x] + 1;
                sp[v[j]].key = sp[v[j]].max = sp[v[j]].min = w[j];
                q[rear ++] = v[j];
            }
    }
}
void Swap(int &x, int &y)
{
    int t;
    t = x, x = y, y = t;
}
void init()
{
    int i;
    memset(first, -1, sizeof(first));
    e = 0;
    scanf("%d", &N);
    for(i = 1; i < N; i ++)
    {
        scanf("%d%d%d", &edge[i].x, &edge[i].y, &edge[i].z);
        add(edge[i].x, edge[i].y, edge[i].z), add(edge[i].y, edge[i].x, edge[i].z);
    }
    prepare();
    for(i = 1; i < N; i ++)
        if(dep[edge[i].x] > dep[edge[i].y])
            Swap(edge[i].x, edge[i].y);
}
void access(int x)
{
    int fx;
    for(fx = x, x = 0; fx != 0; x = fx, fx = sp[x].pre)
    {
        sp[fx].splay(fx);
        sp[sp[fx].rs].root = true;
        sp[fx].rs = x, sp[x].root = false;
        sp[fx].update();
    }
}
void Change(int x, int y)
{
    sp[x].splay(x);
    sp[x].key = y;
    sp[x].update();
}
void Negate(int x, int y)
{
    int fy;
    access(x);
    for(fy = y, y = 0; fy != 0; y = fy, fy = sp[y].pre)
    {
        sp[fy].splay(fy);
        if(sp[fy].pre == 0)
            makeneg(sp[fy].rs), makeneg(y);
        sp[sp[fy].rs].root = true;
        sp[fy].rs = y, sp[y].root = false;
        sp[fy].update();
    }
}
void Query(int x, int y)
{
    int fy;
    access(x);
    for(fy = y, y = 0; fy != 0; y = fy, fy = sp[y].pre)
    {
        sp[fy].splay(fy);
        if(sp[fy].pre == 0)
            printf("%d\n", Max(sp[sp[fy].rs].max, sp[y].max));
        sp[sp[fy].rs].root = true;
        sp[fy].rs = y, sp[y].root = false;
        sp[fy].update();
    }
}
void solve()
{
    int x, y;
    char op[10];
    for(;;)
    {
        scanf("%s", op);
        if(op[0] == 'D')
            break;
        scanf("%d%d", &x, &y);
        if(op[0] == 'C')
            Change(edge[x].y, y);
        else if(op[0] == 'N')
            Negate(x, y);
        else
            Query(x, y);
    }
}
int main()
{
    int t;
    scanf("%d", &t);
    while(t --)
    {
        init();
        solve();
    }
    return 0;
}

来源：https://www.cnblogs.com/staginner/archive/2012/06/16/2551758.html