HDOJ 5296 Annoying problem

根据每次的加点删点求对答案的贡献。。。

#include <iostream>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <bitset>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <climits>
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 100005
#define maxm 200005
#define eps 1e-7
#define mod 1000000007
#define INF 0x3f3f3f3f
#define PI (acos(-1.0))
#define lowbit(x) (x&(-x))
#define mp make_pair
#define ls o<<1
#define rs o<<1 | 1
#define lson o<<1, L, mid 
#define rson o<<1 | 1, mid+1, R
#define pii pair<int, int>
#pragma comment(linker, "/STACK:16777216")
typedef long long LL;
typedef unsigned long long ULL;
//typedef int LL; 
using namespace std;
LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
// head

struct Edge
{
    int v, w;
    Edge *next;
}E[maxm], *H[maxn], *edges;

const int M = 20;
set<pii> s;
set<pii>::iterator t1, t2;
int anc[maxn][20];
bool used[maxn];
int dep[maxn];
int in[maxn];
int dis[maxn];
int n, m, dfs_clock;

void init()
{
    dfs_clock = 0;
    edges = E;
    memset(H, 0, sizeof H);
    memset(used, 0, sizeof used);
}

void addedges(int u, int v, int w)
{
    edges->v = v;
    edges->w = w;
    edges->next = H[u];
    H[u] = edges++;
}

void dfs(int u, int fa)
{
    anc[u][0] = fa;
    in[u] = ++dfs_clock;
    for(Edge *e = H[u]; e; e = e->next) if(e->v != fa) {
        int v = e->v, w = e->w;
        dis[v] = dis[u] + w;
        dep[v] = dep[u] + 1;
        dfs(v, u);
    }
}

int to(int u, int d)
{
    for(int i = M - 1; i >= 0; i--) if(dep[anc[u][i]] >= d) u = anc[u][i];
    return u;
}

int lca(int u, int v)
{
    if(dep[u] < dep[v]) swap(u, v);
    u = to(u, dep[v]);
    for(int i = M - 1; i >= 0; i--) if(anc[u][i] != anc[v][i]) u = anc[u][i], v = anc[v][i];
    return u == v ? u : anc[u][0];
}

void work()
{
    int u, v, w;
    scanf("%d%d", &n, &m);
    for(int i = 1; i < n; i++) {
        scanf("%d%d%d", &u, &v, &w);
        addedges(u, v, w);
        addedges(v, u, w);
    }
    dfs(1, 1);
    for(int j = 1; j < M; j++)
        for(int i = 1; i <= n; i++)
            anc[i][j] = anc[anc[i][j-1]][j-1];
    
    int ans = 0, op;
    s.clear();
    for(int i = 1; i <= m; i++) {
        scanf("%d%d", &op, &u);
        if(op == 1) {
            if(used[u]) goto print;
            else used[u] = 1;
            if(s.empty()) {
                s.insert(mp(in[u], u));
                goto print;
            }
            t1 = s.lower_bound(mp(in[u], u));
            t2 = t1, t2--;
            int a, b;
            if(t1 == s.end() || t1 == s.begin()) t2 = s.begin(), t1 = --s.end();
            a = t2->second, b = t1->second;
            ans += dis[u] + dis[lca(a, b)] - dis[lca(u, b)] - dis[lca(u, a)];
            s.insert(mp(in[u], u));    
        }
        else {
            if(!used[u]) goto print;
            else used[u] = 0;
            s.erase(mp(in[u], u));
            
            t1 = s.lower_bound(mp(in[u], u));
            t2 = t1, t2--;
            int a, b;
            if(t1 == s.end() || t1 == s.begin()) t2 = s.begin(), t1 = --s.end();
            a = t2->second, b = t1->second;
            ans -= dis[u] + dis[lca(a, b)] - dis[lca(u, a)] - dis[lca(u, b)];
        }
print:
        printf("%d\n", ans);
    }
}

int main()
{
    int _;
    scanf("%d", &_);
    for(int i = 1; i <= _; i++) {
        printf("Case #%d:\n", i);
        init();
        work();
    }
    
    return 0;
}