Codeforces: 877E. Danil and a Part-time Job

Solution Idea:

Run a dfs on the given for getting the Euler tour order or inorder traversal order. Then the tree is converted to a liner 1D array. Now we can apply range query and update on this array.

Now use a range update query data structure. Here I have used segment tree. Now initialize the tree with the initial value and now our job is to just toggle a subtree of the given tree and perform query operation. Use a propagation for the update and answer the query.

```
#include &lt;bits/stdc++.h&gt;
#include &lt;ext/pb_ds/assoc_container.hpp&gt;
#include &lt;ext/pb_ds/tree_policy.hpp&gt;

#define pii              pair &lt;int,int&gt;
#define pll              pair &lt;long long,long long&gt;
#define sc               scanf
#define pf               printf
#define Pi               2*acos(0.0)
#define ms(a,b)          memset(a, b, sizeof(a))
#define pb(a)            push_back(a)
#define MP               make_pair
#define db               double
#define ll               long long
#define EPS              10E-10
#define ff               first
#define ss               second
#define sqr(x)           (x)*(x)
#define D(x)             cerr&lt;&lt;#x &quot; = &quot;&lt;&lt;(x)&lt;&lt;endl
#define VI               vector &lt;int&gt;
#define DBG              pf(&quot;Hi\n&quot;)
#define MOD              1000000007
#define CIN              ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define SZ(a)            (int)a.size()
#define sf(a)            scanf(&quot;%d&quot;,&amp;a)
#define sfl(a)           scanf(&quot;%lld&quot;,&amp;a)
#define sff(a,b)         scanf(&quot;%d %d&quot;,&amp;a,&amp;b)
#define sffl(a,b)        scanf(&quot;%lld %lld&quot;,&amp;a,&amp;b)
#define sfff(a,b,c)      scanf(&quot;%d %d %d&quot;,&amp;a,&amp;b,&amp;c)
#define sfffl(a,b,c)     scanf(&quot;%lld %lld %lld&quot;,&amp;a,&amp;b,&amp;c)
#define stlloop(v)       for(__typeof(v.begin()) it=v.begin();it!=v.end();it++)
#define loop(i,n)        for(int i=0;i&lt;n;i++)
#define loop1(i,n)       for(int i=1;i&lt;=n;i++)
#define REP(i,a,b)       for(int i=a;i&lt;b;i++)
#define RREP(i,a,b)      for(int i=a;i&gt;=b;i--)
#define TEST_CASE(t)     for(int z=1;z&lt;=t;z++)
#define PRINT_CASE       printf(&quot;Case %d: &quot;,z)
#define LINE_PRINT_CASE  printf(&quot;Case %d:\n&quot;,z)
#define CASE_PRINT       cout&lt;&lt;&quot;Case &quot;&lt;&lt;z&lt;&lt;&quot;: &quot;
#define all(a)           a.begin(),a.end()
#define intlim           2147483648
#define infinity         (1&lt;&lt;28)
#define ull              unsigned long long
#define gcd(a, b)        __gcd(a, b)
#define lcm(a, b)        ((a)*((b)/gcd(a,b)))

using namespace std;

//using namespace __gnu_pbds;
//typedef tree&lt;int, null_type, less&lt;int&gt;, rb_tree_tag, tree_order_statistics_node_update&gt; ordered_set;

/*----------------------Graph Moves----------------*/
//const int fx[]={+1,-1,+0,+0};
//const int fy[]={+0,+0,+1,-1};
//const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1};   // Kings Move
//const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1};  // Kings Move
//const int fx[]={-2, -2, -1, -1,  1,  1,  2,  2};  // Knights Move
//const int fy[]={-1,  1, -2,  2, -2,  2, -1,  1}; // Knights Move
/*------------------------------------------------*/

//int Set(int N,int pos){return N=N | (1&lt;&lt;pos);}
//int reset(int N,int pos){return N= N &amp; ~(1&lt;&lt;pos);}
//bool check(int N,int pos){return (bool)(N &amp; (1&lt;&lt;pos));}
/*------------------------------------------------*/

#define mx 200005
#define segment_tree int l=n*2,r=l+1,mid=(b+e)/2
pii info[mx];
vector&lt;int&gt;g[mx];
int cnt=0;
int maps[mx],ara[mx];

void dfs(int u, int par)
{
info[u].ff=++cnt;
maps[cnt]=u;
for(int i=0;i&lt;SZ(g[u]);i++)
{
int v=g[u][i];
if(v==par) continue;
dfs(v,u);
}
info[u].ss=cnt;
}

struct data
{
int val, prop;
};

data tree[3*mx];

void push_down(int n, int b, int e)
{
if(tree[n].prop%2)
{
segment_tree;
tree[l].val=(mid-b+1)-tree[l].val;
tree[l].prop++;
tree[r].val=(e-mid)-tree[r].val;
tree[r].prop++;
tree[n].prop=0;
}
}

void init(int n, int b, int e)
{
if(b==e)
{
tree[n].val=ara[maps[b]];
tree[n].prop=0;
return;
}
segment_tree;
init(l,b,mid);
init(r,mid+1,e);
tree[n].val=tree[l].val+tree[r].val;
}

void update(int n, int b, int e, int i, int j)
{
if(b&gt;j || e&lt;i) return;
if(b&gt;=i &amp;&amp; e&lt;=j)
{
tree[n].val=(e-b+1)-tree[n].val;
tree[n].prop++;
return;
}
push_down(n,b,e);
segment_tree;
update(l,b,mid,i,j);
update(r,mid+1,e,i,j);
tree[n].val=tree[l].val+tree[r].val;
}

int query(int n, int b, int e, int i, int j)
{
if(b&gt;j || e&lt;i) return 0;
if(b&gt;=i &amp;&amp; e&lt;=j) return tree[n].val;
push_down(n,b,e);
segment_tree;
int p=query(l,b,mid,i,j);
int q=query(r,mid+1,e,i,j);
return p+q;
}

char str[10];

int main()
{

//    freopen(&quot;in.txt&quot;,&quot;r&quot;,stdin);
//	  freopen(&quot;out.txt&quot;,&quot;w&quot;,stdout);

int n;
sf(n);
for(int i=2;i&lt;=n;i++)
{
int a;
sf(a);
g[a].pb(i);
}

for(int i=1;i&lt;=n;i++) sf(ara[i]);
dfs(1,1);
init(1,1,n);
int q;
sf(q);
while(q--)
{
int a;
scanf(&quot; %s %d&quot;,str,&amp;a);
if(str[0]=='g')
{
int x=query(1,1,n,info[a].ff,info[a].ss);
printf(&quot;%d\n&quot;,x);
}
else
{
update(1,1,n,info[a].ff,info[a].ss);
}
}

return 0;
}

```