Untitled

#include 
#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;
typedef long long ll;
const int maxn = 2e5 + 10;
const int logn = 18;
int parent[maxn];
int up_node[maxn][logn + 5];
int depth_of_node[maxn];
int main() {
    ios_base::sync_with_stdio(false);
    int n, q;
    cin >> n >> q;
    
    for(int i = 1; i < n; i++) {
        int p;
        cin >> p;
        p--;
        parent[i] = p;
    }
    memset(depth_of_node, 0, sizeof depth_of_node);
    memset(up_node, 0, sizeof up_node);
    parent[0] = 0;
    
    for(int i = 0; i < n; i++) {
        up_node[i][0] = parent[i];
        if(i != 0) {
            depth_of_node[i] = depth_of_node[parent[i]] + 1;
        }
        
        for(int j = 1; j <= logn; j++) {
            up_node[i][j] = up_node[ up_node[i][j - 1] ][j - 1];
        }
    }
    
  
    
    while(q--) {
        int node, k;
        cin >> node >> k;
        node--;
        if(depth_of_node[node] < k) {
            cout << -1 << endl;
            continue;
        }
        for(int i = logn; i >= 0; i--) {
            if(node == -1) {
                break;
            }
            if(k & (1 << i)) {
                node = up_node[node][i];
            }
            
        }
        if(node != -1) {
            node++;
        }
        cout << node << endl;
    }
    
    return 0;
}

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