78 lines
2.0 KiB
Java
78 lines
2.0 KiB
Java
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//Problem Statement
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// 1. You are given a number n, representing the number of people in a party.
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// 2. You are given n strings of n length containing 0's and 1's
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// 3. If there is a '1' in ith row, jth spot, then person i knows about person j.
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// 4. A celebrity is defined as somebody who knows no other person than himself but everybody else knows him.
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// 5. If there is a celebrity print it's index otherwise print "none".
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//solution
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import java.io.*;
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import java.util.*;
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public class Main {
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public static void main(String[] args) throws Exception {
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// write your code here
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BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
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int n = Integer.parseInt(br.readLine());
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int[][] arr = new int[n][n];
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for (int j = 0; j < n; j++) {
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String line = br.readLine();
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for (int k = 0; k < n; k++) {
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arr[j][k] = line.charAt(k) - '0';
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}
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}
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findCelebrity(arr);
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}
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public static void findCelebrity(int[][] arr) {
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// if a celebrity is there print it's index (not position), if there is not then print "none"
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Stack < Integer > st = new Stack < > ();
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for (int i = 0; i < arr.length; i++) {
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st.push(i);
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}
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while (st.size() > 1) {
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int i = st.pop();
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int j = st.pop();
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if (arr[i][j] == 1) {
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st.push(j);
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} else {
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st.push(i);
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}
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}
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int pot = st.pop();
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boolean flag = true;
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for (int i = 0; i < arr.length; i++) {
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if (i != pot) {
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if (arr[i][pot] == 0 || arr[pot][i] == 1) {
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flag = false;
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break;
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}
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}
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}
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if (flag) {
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System.out.println(pot);
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} else {
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System.out.println("none");
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}
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}
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}
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//Test Case:-
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//Input
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// 4
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// 0000
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// 1011
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// 1101
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// 1110
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//Output
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//0
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