C. Propagating tree
time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

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.

Examples
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)

思路:dfs序+线段树;

首先dfs序映射一下,然后转换成然后线段树维护,新然后开两个数组,一个作为正一个作为负。

复杂度n×log(n);

  1 #include<stdio.h>
2 #include<algorithm>
3 #include<queue>
4 #include<stdlib.h>
5 #include<iostream>
6 #include<string.h>
7 #include<set>
8 #include<map>
9 #include<vector>
10 using namespace std;
11 typedef long long LL;
12 int ans[200005];
13 int id[200005];
14 int a[200005];
15 typedef vector<int> Ve;
16 vector<Ve>vec(200005);
17 bool flag[200005];
18 int cn = 0;
19 int l[200005];
20 int r[200005];
21 void dfs(int n,int p);
22 int tree1[200005*4];
23 int tree2[4*200005];
24 void update(int x,int n,int c);
25 int ask(int x);
26 int jiou[200005];
27 void update(int l,int r,int k,int nn,int mm,int co,int p)
28 {
29 if(l > mm||r < nn)
30 {
31 return ;
32 }
33 else if(l <= nn&& r >= mm)
34 {
35 if(p%2)tree1[k]+=co;
36 else tree2[k]+=co;
37 return ;
38 }
39 else
40 {
41 update(l,r,2*k+1,nn,(nn+mm)/2,co,p);
42 update(l,r,2*k+2,(nn+mm)/2+1,mm,co,p);
43 }
44 }
45 int ask1(int l,int r,int k,int nn,int mm)
46 {
47 if(l > mm || r < nn)
48 return 0;
49 else if(l <= nn&&r >= mm)
50 {
51 return tree1[k];
52 }
53 else
54 {
55 tree1[2*k+1] += tree1[k];
56 tree1[2*k+2] += tree1[k];
57 tree1[k] = 0;
58 int nx = ask1(l,r,2*k+1,nn,(nn+mm)/2);
59 int ny = ask1(l,r,2*k+2,(nn+mm)/2+1,mm);
60 return nx + ny;
61 }
62 }
63 int ask2(int l,int r,int k,int nn,int mm)
64 {
65 if(l > mm || r < nn)
66 return 0;
67 else if(l <= nn&&r >= mm)
68 {
69 return tree2[k];
70 }
71 else
72 {
73 tree2[2*k+1] += tree2[k];
74 tree2[2*k+2] += tree2[k];
75 tree2[k] = 0;
76 int nx = ask2(l,r,2*k+1,nn,(nn+mm)/2);
77 int ny = ask2(l,r,2*k+2,(nn+mm)/2+1,mm);
78 return nx + ny;
79 }
80 }
81 int main(void)
82 {
83 int n,m;
84 scanf("%d %d",&n,&m);
85 for(int i = 1; i <= n; i++)
86 {
87 scanf("%d",&a[i]);
88 }
89 for(int i = 1; i < n; i++)
90 {
91 int x,y;
92 scanf("%d %d",&x,&y);
93 vec[x].push_back(y);
94 vec[y].push_back(x);
95 }
96 dfs(1,1);
97 for(int i = 1; i <= n; i++)
98 id[ans[i]] = i;
99 while(m--)
100 {
101 int val;
102 int co,ic;
103 scanf("%d %d",&val,&ic);
104 if(val == 1)
105 {
106 scanf("%d",&co);
107 update(l[ic],r[ic],0,1,cn,co,jiou[ic]);
108 }
109 else
110 {
111 int xx = ask1(id[ic],id[ic],0,1,cn);
112 int yy = ask2(id[ic],id[ic],0,1,cn);
113 //printf("%d\n",xx);
114 if(jiou[ic]%2)
115 {
116 printf("%d\n",xx-yy+a[ic]);
117 }
118 else printf("%d\n",yy-xx+a[ic]);
119 }
120 }
121 return 0;
122 }
123 void dfs(int n,int p)
124 {
125 flag[n] = true;
126 ans[++cn] = n;
127 l[n] = cn;
128 jiou[n] = p;
129 for(int i = 0; i < vec[n].size(); i++)
130 {
131 int x = vec[n][i];
132 if(!flag[x])
133 dfs(x,p+1);
134 }
135 r[n] = cn;
136 }

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