1036: [ZJOI2008]樹的統計Count樹鏈剖分

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　　雖然是水題一枚，但是在我的不懈努下，交了80幾發，在突然有一天重寫的情況下，竟然1a了。

#include<iostream>#include<cstdio>#include<cstring>#include<map>#include<vector>#include<stdlib.h>using namespace std;const int maxn = 33333;struct Node{    int next; int to;}e[maxn*2];int len, z;#define lson l,mid,rt<<1#define rson mid+1,r,rt<<1|1int head[maxn], top[maxn], son[maxn], father[maxn], size[maxn], deep[maxn], pos[maxn], val[maxn], vis[maxn];int sum[maxn<<2],Max[maxn<<2];void add(int from, int to){    e[len].to = to;    e[len].next = head[from];    head[from] = len++;}void init(int x){    size[x] = 1; son[x] = 0;    for (int i = head[x]; ~i; i = e[i].next){        int cc = e[i].to;        if (cc == father[x]) continue;        deep[cc] = deep[x] + 1; father[cc] = x;        init(cc);        size[x] += size[cc];        if (size[son[x]] < size[cc]) son[x] = cc;    }}void dfs(int x, int tp){    pos[x] = ++z; vis[z] = x; top[x] = tp;    if(son[x]) dfs(son[x],tp);    for (int i = head[x]; i != -1; i = e[i].next){        int cc = e[i].to;        if (cc == father[x] || cc == son[x]) continue;        dfs(cc, cc);    }}void up(int rt){    sum[rt] = sum[rt << 1] + sum[rt << 1 | 1];    Max[rt] = max(Max[rt << 1], Max[rt << 1 | 1]);}void build(int l, int r, int rt){    if (l == r){        Max[rt] = sum[rt] = val[vis[l]]; return;    }    int mid = (l + r) >> 1;    build(lson);    build(rson);    up(rt);}void update(int key, int ans, int l, int r, int rt){    if (l == r){        Max[rt] = sum[rt] = ans; return;    }    int mid = (l + r) >> 1;    if (key <= mid) update(key, ans, lson);    else update(key, ans, rson);    up(rt);}int ask_max(int L, int R, int l, int r, int rt){    if (L <= l&&r <= R) return Max[rt];    int ans = -1e9;    int mid = (l + r) >> 1;    if (L <= mid) ans = max(ans, ask_max(L, R, lson));    if (R > mid) ans = max(ans, ask_max(L, R, rson));    return ans;}int ask_sum(int L, int R, int l, int r, int rt){    if (L <= l&&r <= R) return sum[rt];    int ans = 0;    int mid = (l + r) >> 1;    if (L <= mid) ans += ask_sum(L, R, lson);    if (R > mid) ans += ask_sum(L, R, rson);    return ans;}void gao_max(int x, int y){    int ans = -1e9;    int fx = top[x]; int fy = top[y];    while (fx != fy){        if (deep[fx] < deep[fy]){            swap(x, y); swap(fx, fy);        }        ans = max(ans, ask_max(pos[fx], pos[x], 1, z, 1));        x = father[fx]; fx = top[x];    }    if (deep[x]>deep[y]){        swap(x, y);    }    ans = max(ans, ask_max(pos[x], pos[y], 1, z, 1));    printf("%d\n", ans);}void gao_sum(int x, int y){    int ans = 0;    int fx = top[x]; int fy = top[y];    while (fx != fy){        if (deep[fx] < deep[fy]){            swap(x, y); swap(fx, fy);        }        ans += ask_sum(pos[fx], pos[x], 1, z, 1);        x = father[fx]; fx = top[x];    }    if (deep[x]>deep[y]) swap(x, y);    ans += ask_sum(pos[x], pos[y], 1, z, 1);    printf("%d\n", ans);}int main(){    int n;    int a, b, c;    int q;    char str[1000];    while (cin >> n){        len = z = 0;        memset(head, -1, sizeof(head));        for (int i = 0; i < n - 1; i++){            cin >> a >> b; add(a, b); add(b, a);        }        for (int i = 1; i <= n; i++){            scanf("%d", &val[i]);        }        init(1); dfs(1, 1); build(1, z, 1);        cin >> q;        while (q--){            scanf("%s%d%d", str, &a, &b);            if (strcmp(str, "QMAX") == 0){                gao_max(a, b);            }            else if (strcmp(str, "QSUM") == 0){                gao_sum(a, b);            }            else update(pos[a], b, 1, z, 1);        }    }    return 0;}

 

1036: [ZJOI2008]樹的統計Count樹鏈剖分