Codeforces Round #225 (Div. 2)---E. Propagating tree(时间戳+线段树)

Iahub likes trees very much. Recently he discovered an interesting tree named propagating tree. The tree consists of n nodes numbered from 1 to n, each node i having an initial value ai. The root of the tree is node 1.

This tree has a special property: when a value val is added to a value of node i, the value -val is added to values of all the children of node i. Note that when you add value -val to a child of node i, you also add -(-val) to all children of the child of node i and so on. Look an example explanation to understand better how it works.

This tree supports two types of queries:

"1 x val" — val is added to the value of node x;
"2 x" — print the current value of node x. 

In order to help Iahub understand the tree better, you must answer m queries of the preceding type.
Input

The first line contains two integers n and m (1 ≤ n, m ≤ 200000). The second line contains n integers a1, a2, …, an (1 ≤ ai ≤ 1000). Each of the next n–1 lines contains two integers vi and ui (1 ≤ vi, ui ≤ n), meaning that there is an edge between nodes vi and ui.

Each of the next m lines contains a query in the format described above. It is guaranteed that the following constraints hold for all queries: 1 ≤ x ≤ n, 1 ≤ val ≤ 1000.
Output

For each query of type two (print the value of node x) you must print the answer to the query on a separate line. The queries must be answered in the order given in the input.
Sample test(s)
Input

5 5
1 2 1 1 2
1 2
1 3
2 4
2 5
1 2 3
1 1 2
2 1
2 2
2 4

Output

3
3
0

Note

The values of the nodes are [1, 2, 1, 1, 2] at the beginning.

Then value 3 is added to node 2. It propagates and value -3 is added to it’s sons, node 4 and node 5. Then it cannot propagate any more. So the values of the nodes are [1, 5, 1,  - 2,  - 1].

Then value 2 is added to node 1. It propagates and value -2 is added to it’s sons, node 2 and node 3. From node 2 it propagates again, adding value 2 to it’s sons, node 4 and node 5. Node 3 has no sons, so it cannot propagate from there. The values of the nodes are [3, 3,  - 1, 0, 1].

You can see all the definitions about the tree at the following link: http://en.wikipedia.org/wiki/Tree_(graph_theory)

很明显要先跑一个dfs得到时间戳,但是这还不够,这里对某个节点加上某个数以后,它的儿子要减去那个数,它儿子的儿子要加上那个数,所以我们要根据深度的奇偶,把时间戳搞成2个数组,建立2颗线段树

/*************************************************************************
    > File Name: CF225-E.cpp
    > Author: ALex
    > Mail: [email protected] 
    > Created Time: 2015年04月21日 星期二 21时11分04秒
 ************************************************************************/

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

using namespace std;

const double pi = acos(-1.0);
const int inf = 0x3f3f3f3f;
const double eps = 1e-15;
typedef long long LL;
typedef pair <int, int> PLL;

static const int N = 300010;

int par[N];
int oddL[N];
int oddR[N];
int evenL[N];
int evenR[N];
int subL[N];
int subR[N];
int dep[N];
int arr[N];
int now[N];
int sta[N];
int is_leaf[N];

struct node{
    int add;
    int l, r;
    int sum;
}tree[2][N << 2];

struct EDGE {
    int to;
    int nxt;
}edge[N << 1];
int head[N], tot;

void addedge(int from, int to) {
    edge[tot].to = to;
    edge[tot].nxt = head[from];
    head[from] = tot++;
}

void build(node tree[], int p, int l, int r) {
    tree[p].l = l;
    tree[p].r = r;
    tree[p].add = 0;
    if (l == r) {
        tree[p].sum = now[l];
        return;
    }   
    int mid = (l + r) >> 1;
    build(tree, p << 1, l, mid);
    build(tree, p << 1 | 1, mid + 1, r);
    tree[p].sum = tree[p << 1].sum + tree[p << 1 | 1].sum;
}

void pushdown(node tree[], int p) {
    if (tree[p].add) {
        tree[p << 1].add += tree[p].add;
        tree[p << 1 | 1].add += tree[p].add;
        int m = tree[p << 1].r - tree[p << 1].l + 1;
        tree[p << 1].sum += m * tree[p].add;
        m = tree[p << 1 | 1].r - tree[p << 1 | 1].l + 1;
        tree[p << 1 | 1].sum += m * tree[p].add;
        tree[p].add = 0;
    }
}

void update(node tree[], int p, int l, int r, int val) {
    if (l == tree[p].l && r == tree[p].r) {
        tree[p].add += val;
        int m = r - l + 1;
        tree[p].sum += m * val;
        return;
    }
    pushdown(tree, p);
    int mid = (tree[p].l + tree[p].r) >> 1;
    if (r <= mid) {
        update(tree, p << 1, l, r, val);
    }
    else if (l > mid) {
        update(tree, p << 1 | 1, l, r, val);
    }
    else {
        update(tree, p << 1, l, mid, val);
        update(tree, p << 1 | 1, mid + 1, r, val);
    }
    tree[p].sum = tree[p << 1].sum + tree[p << 1 | 1].sum;
}

int query(node tree[], int p, int pos) {
    if (tree[p].l == tree[p].r) {
        return tree[p].sum;
    }
    pushdown(tree, p);
    int mid = (tree[p].l + tree[p].r) >> 1;
    if (pos <= mid) {
        return query(tree, p << 1, pos);
    }
    else {
        return query(tree, p << 1 | 1, pos);
    }
}

void getDepth(int u, int fa, bool flag) { // 1 -> 奇数, 2 -> 偶数
    par[u] = fa;
    dep[u] = flag;
    bool ok = 1;
    for (int i = head[u]; ~i; i = edge[i].nxt) {
        int v = edge[i].to;
        if (v == fa) {
            continue;
        }
        getDepth(v, u, flag ^ 1);
        ok = 0;
    }
    is_leaf[u] = ok;
}

void dfs1(int u, int fa, int &ret) { 
    if (dep[u]) {
        oddL[u] = ++ret;
    }
    for (int i = head[u]; ~i; i = edge[i].nxt) {
        int v = edge[i].to;
        if (v == fa) {
            continue;
        }
        dfs1(v, u, ret);
    }
    if (dep[u]) {
        oddR[u] = ret;
    }
}

void dfs2(int u, int fa, int &ret) {
    if (!dep[u]) {
        evenL[u] = ++ret;
    }
    for (int i = head[u]; ~i; i = edge[i].nxt) {
        int v = edge[i].to;
        if (v == fa) {
            continue;
        }
        dfs2(v, u, ret);
    }
    if (!dep[u]) {
        evenR[u] = ret;
    }
}

int main() {
    int n, m;
    while (~scanf("%d%d", &n, &m)) {
        for (int i = 1; i <= n; ++i) {
            scanf("%d", &arr[i]);
        }
        memset(head, -1, sizeof(head));
        memset(is_leaf, 0, sizeof(is_leaf));
        tot = 0;
        int u, v;
        for (int i = 1; i <= n - 1; ++i) {
            scanf("%d%d", &u, &v);
            addedge(u, v);
            addedge(v, u);
        }
        int L1 = 0, L2 = 0;
        getDepth(1, -1, 1);
        dfs1(1, -1, L1);
        dfs2(1, -1, L2); //偶数
        for (int i = 1; i <= n; ++i) {
            subL[i] = inf;
            subR[i] = -inf;
            if (is_leaf[i]) {
                continue;
            }
            for (int j = head[i]; ~j; j = edge[j].nxt) {
                if (edge[j].to == par[i]) {
                    continue;
                }
                if (dep[i]) {
                    subL[i] = min(subL[i], evenL[edge[j].to]);
                    subR[i] = max(subR[i], evenR[edge[j].to]);
                }
                else {
                    subL[i] = min(subL[i], oddL[edge[j].to]);
                    subR[i] = max(subR[i], oddR[edge[j].to]);
                }
            }
        }
        for (int i = 1; i <= n; ++i) {
            if (!dep[i]) { //偶数
                now[evenL[i]] = arr[i];
            }
        }
        if (L2 >= 1) {
            build(tree[0], 1, 1, L2);
        }
        for (int i = 1; i <= n; ++i) {
            if (dep[i]) {
                now[oddL[i]] = arr[i];
            }
        }
        if (L1 >= 1) {
            build(tree[1], 1, 1, L1);
        }
        int op, x, y;
        while (m--) {
            scanf("%d", &op);
            if (op == 1) {
                scanf("%d%d", &x, &y);
                if (dep[x]) {
                    int l = oddL[x];
                    int r = oddR[x];
                    update(tree[1], 1, l, r, y);
                    if (!is_leaf[x]) {
                        l = subL[x];
                        r = subR[x];
                        update(tree[0], 1, l, r, -y);
                    }
                }
                else {
                    int l = evenL[x];
                    int r = evenR[x];
                    update(tree[0], 1, l, r, y);
                    if (!is_leaf[x]) {
                        l = subL[x];
                        r = subR[x];
                        update(tree[1], 1, l, r, -y);
                    }
                }
            }
            else {
                scanf("%d", &x);
                if (dep[x]) {
                    printf("%d\n", query(tree[1], 1, oddL[x]));
                }
                else {
                    printf("%d\n", query(tree[0], 1, evenL[x]));
                }
            }
        }
    }
    return 0;
}