Related Articles
Find the node whose xor with x gives minimum value
• Difficulty Level : Medium
• Last Updated : 16 Apr, 2021

Given a tree, and the weights of all the nodes and an integer x, the task is to find a node i such that weight[i] xor x is minimum.
Examples:

Input:

x = 15
Output:
Node 1: 5 xor 15 = 10
Node 2: 10 xor 15 = 5
Node 3: 11 xor 15 = 4
Node 4: 8 xor 15 = 7
Node 5: 6 xor 15 = 9

Approach: Perform dfs on the tree and keep track of the node whose weighted xor with x gives the minimum value.
Below is the implementation of above approach:

## C++

 // C++ implementation of the approach#include using namespace std; int minimum = INT_MAX, x, ans; vector graph[100];vector weight(100); // Function to perform dfs to find// the minimum xored valuevoid dfs(int node, int parent){    // If current value is less than    // the current minimum    if (minimum > (weight[node] ^ x)) {        minimum = weight[node] ^ x;        ans = node;    }    for (int to : graph[node]) {        if (to == parent)            continue;        dfs(to, node);    }} // Driver codeint main(){    x = 15;     // Weights of the node    weight[1] = 5;    weight[2] = 10;    weight[3] = 11;    weight[4] = 8;    weight[5] = 6;     // Edges of the tree    graph[1].push_back(2);    graph[2].push_back(3);    graph[2].push_back(4);    graph[1].push_back(5);     dfs(1, 1);     cout << ans;     return 0;}

## Java

 // Java implementation of the approachimport java.util.*;import java.lang.*; class GFG{     static int minimum = Integer.MAX_VALUE, x, ans;     @SuppressWarnings("unchecked")    static Vector[] graph = new Vector[100];    static int[] weight = new int[100];     // This block is executed even before main() function    // This is necessary otherwise this program will    // throw "NullPointerException"    static    {        for (int i = 0; i < 100; i++)            graph[i] = new Vector<>();    }     // Function to perform dfs to find    // the minimum xored value    static void dfs(int node, int parent)    {         // If current value is less than        // the current minimum        if (minimum > (weight[node] ^ x))        {            minimum = weight[node] ^ x;            ans = node;        }        for (int to : graph[node])        {            if (to == parent)                continue;            dfs(to, node);        }    }     // Driver Code    public static void main(String[] args)    {        x = 15;         // Weights of the node        weight[1] = 5;        weight[2] = 10;        weight[3] = 11;        weight[4] = 8;        weight[5] = 6;         // Edges of the tree        graph[1].add(2);        graph[2].add(3);        graph[2].add(4);        graph[1].add(5);         dfs(1, 1);         System.out.println(ans);    }} // This code is contributed by SHUBHAMSINGH10

## Python3

 # Python implementation of the approachfrom sys import maxsize minimum, x, ans = maxsize, None, None graph = [[] for i in range(100)]weight = [0] * 100 # Function to perform dfs to find# the minimum xored valuedef dfs(node, parent):    global x, ans, graph, weight, minimum     # If current value is less than    # the current minimum    if minimum > weight[node] ^ x:        minimum = weight[node] ^ x        ans = node     for to in graph[node]:        if to == parent:            continue        dfs(to, node) # Driver Codeif __name__ == "__main__":     x = 15     # Weights of the node    weight[1] = 5    weight[2] = 10    weight[3] = 11    weight[4] = 8    weight[5] = 6     # Edges of the tree    graph[1].append(2)    graph[2].append(3)    graph[2].append(4)    graph[1].append(5)     dfs(1, 1)     print(ans) # This code is contributed by# sanjeev2552

## Javascript


Output:
3

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.  To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.

In case you wish to attend live classes with industry experts, please refer Geeks Classes Live

My Personal Notes arrow_drop_up