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  1. #include<bits/stdc++.h>
  2.  
  3. using namespace std;
  4.  
  5. long long build(long long* tree,int i,int tl,int tr,int* a,int op)
  6. {
  7.     if(tl==tr)
  8.     {
  9.         tree[i]=a[tl];
  10.         return tree[i];
  11.     }
  12.     int m=(tl+tr)/2;
  13.  
  14.    //changed here
  15.     tree[2*i+1]=build(tree,2*i+1,tl,m,a,!op);
  16.     tree[2*i+2]=build(tree,2*i+2,m+1,tr,a,!op);
  17.  
  18.     if(op==1)
  19.          tree[i] = tree[2*i+1]|tree[2*i+2];
  20.     else
  21.          tree[i] = tree[2*i+1]^tree[2*i+2];
  22.     return tree[i];
  23.  
  24. }
  25.  
  26.  
  27.  
  28. long long update(long long* tree,int i,int tl,int tr,int l,int* a,int op) 
  29. {
  30.     if(tl==tr && tl==l)
  31.     {
  32.         tree[i]=a[l];
  33.         return tree[i];
  34.     }
  35.     if(l<tl || l>tr)
  36.     {
  37.         return tree[i];
  38.     }
  39.     int m=(tl+tr)/2;
  40.     //changed here
  41.     tree[2*i+1]=update(tree,2*i+1,tl,m,l,a,!op);
  42.     tree[2*i+2]=update(tree,2*i+2,m+1,tr,l,a,!op);
  43.     if(op==1)
  44.          tree[i] = tree[2*i+1] | tree[2*i+2];
  45.     else
  46.          tree[i] = tree[2*i+1] ^ tree[2*i+2];
  47.     return tree[i];
  48. }
  49.  
  50.  
  51. int main()
  52. {
  53.     int n,q; cin >> n>>q;
  54.     int s=pow(2,n);
  55.     int a[s];
  56.     for(int i=0;i<s;i++) cin >> a[i];
  57.     //height of tree
  58.     int x = (int)(ceil(log2(s)));
  59.     long long tree[4*s];
  60.     int op;
  61.     if(x%2==0)
  62.     {
  63.         op=0;
  64.     }
  65.     else op=1;
  66.     build(tree,0,0,s-1,a,op);
  67.  
  68.  
  69.  
  70.  
  71.     while(q--)
  72.     {
  73.  
  74.             int l,v; cin >> l>> v;
  75.             l--;
  76.             a[l]=v;
  77.             long long stree=update(tree,0,0,s-1,l,a,op);
  78.  
  79.             cout << stree << endl;
  80.  
  81.  
  82.     }
  83.  
  84.     return 0;
  85. }
  86.  
Success #stdin #stdout 0.01s 5304KB
comments (?)
stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/7mP7fI
language:
C++ (gcc 8.3)
created:
3 hours ago
visibility:
public

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