Bigger is Greater – HackerRank Solution

In this post, we will solve Bigger is Greater HackerRank Solution. This problem (Bigger is Greater) is a part of HackerRank Algorithms series.

Task

Lexicographical order is often known as alphabetical order when dealing with strings. A string is greater than another string if it comes later in a lexicographically sorted list.

Given a word, create a new word by swapping some or all of its characters. This new word must meet two criteria:

• It must be greater than the original word
• It must be the smallest word that meets the first condition

Example
w = abcd

The next largest word is abdc.

Complete the function biggerIsGreater below to create and return the new string meeting the criteria. If it is not possible, return no answer.

Function Description

Complete the biggerIsGreater function in the editor below.

biggerIsGreater has the following parameter(s):

• string w: a word

Returns
– string: the smallest lexicographically higher string possible or no answer

Input Format

The first line of input contains T, the number of test cases.
Each of the next T lines contains w.

Constraints

• 1 <= T <= 10⁵
• 1 <= lengthofw <= 100
• w will contain only letters in the range ascii[a..z].

Sample Input 0

5
ab
bb
hefg
dhck
dkhc

Sample Output 0

ba
no answer
hegf
dhkc
hcdk

Explanation 0

• Test case 1:
  ba is the only string which can be made by rearranging ab. It is greater.
• Test case 2:
  It is not possible to rearrange bb and get a greater string.
• Test case 3:
  hegf is the next string greater than hefg.
• Test case 4:
  dhkc is the next string greater than dhck.
• Test case 5:
  hcdk is the next string greater than dkhc.

Sample Input 1

6
lmno
dcba
dcbb
abdc
abcd
fedcbabcd

Sample Output 1

lmon
no answer
no answer
acbd
abdc
fedcbabdc

Solution – Bigger is Greater – HackerRank Solution

C++

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

 string s;

int main() {
    int tc;
    scanf("%d", &tc);
    while (tc--) {
        cin >> s;
        if (next_permutation(s.begin(), s.end())) printf("%s\n", s.c_str());
        else printf("no answer\n");
    }
    return 0;
}

Python

#!/bin/python3

import sys
from itertools import permutations

def biggerIsGreater(w):
    arr = list(w)
    # Find non-increasing suffix
    i = len(arr) - 1
    while i > 0 and arr[i - 1] >= arr[i]:
            i -= 1
    if i <= 0:
        return 'no answer'
    
    # Find successor to pivot
    j = len(arr) - 1
    while arr[j] <= arr[i - 1]:
        j -= 1
    arr[i - 1], arr[j] = arr[j], arr[i - 1]
    
    # Reverse suffix
    arr[i : ] = arr[len(arr) - 1 : i - 1 : -1]
       
    return "".join(arr)
     

if __name__ == "__main__":
    T = int(input().strip())
    for a0 in range(T):
        w = input().strip()
        result = biggerIsGreater(w)
        print(result)

Java

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class Solution {
    static InputStream is;
    static PrintWriter out;
    static String INPUT = "";
    
    static void solve()
    {
        outer:
        for(int T = ni();T >= 1;T--){
            char[] s = ns().toCharArray();
            int n = s.length;
            int[] has = new int[26];
            for(int i = n-1;i >= 0;i--){
                has[s[i]-'a']++;
                for(int j = s[i]-'a'+1;j < 26;j++){
                    if(has[j] > 0){
                        s[i] = (char)('a'+j);
                        has[j]--;
                        int p = 0;
                        for(int k = i+1;k < n;k++){
                            while(p < 26 && has[p] == 0)p++;
                            s[k] = (char)('a'+p);
                            has[p]--;
                        }
                        out.println(new String(s));
                        continue outer;
                    }
                }
            }
            out.println("no answer");
        }
    }
    
    public static void main(String[] args) throws Exception
    {
        long S = System.currentTimeMillis();
        is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
        out = new PrintWriter(System.out);
        
        solve();
        out.flush();
        long G = System.currentTimeMillis();
        tr(G-S+"ms");
    }
    
    private static boolean eof()
    {
        if(lenbuf == -1)return true;
        int lptr = ptrbuf;
        while(lptr < lenbuf)if(!isSpaceChar(inbuf[lptr++]))return false;
        
        try {
            is.mark(1000);
            while(true){
                int b = is.read();
                if(b == -1){
                    is.reset();
                    return true;
                }else if(!isSpaceChar(b)){
                    is.reset();
                    return false;
                }
            }
        } catch (IOException e) {
            return true;
        }
    }
    
    private static byte[] inbuf = new byte[1024];
    static int lenbuf = 0, ptrbuf = 0;
    
    private static int readByte()
    {
        if(lenbuf == -1)throw new InputMismatchException();
        if(ptrbuf >= lenbuf){
            ptrbuf = 0;
            try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
            if(lenbuf <= 0)return -1;
        }
        return inbuf[ptrbuf++];
    }
    
    private static boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
    private static int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
    
    private static double nd() { return Double.parseDouble(ns()); }
    private static char nc() { return (char)skip(); }
    
    private static String ns()
    {
        int b = skip();
        StringBuilder sb = new StringBuilder();
        while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    
    private static char[] ns(int n)
    {
        char[] buf = new char[n];
        int b = skip(), p = 0;
        while(p < n && !(isSpaceChar(b))){
            buf[p++] = (char)b;
            b = readByte();
        }
        return n == p ? buf : Arrays.copyOf(buf, p);
    }
    
    private static char[][] nm(int n, int m)
    {
        char[][] map = new char[n][];
        for(int i = 0;i < n;i++)map[i] = ns(m);
        return map;
    }
    
    private static int[] na(int n)
    {
        int[] a = new int[n];
        for(int i = 0;i < n;i++)a[i] = ni();
        return a;
    }
    
    private static int ni()
    {
        int num = 0, b;
        boolean minus = false;
        while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
        if(b == '-'){
            minus = true;
            b = readByte();
        }
        
        while(true){
            if(b >= '0' && b <= '9'){
                num = num * 10 + (b - '0');
            }else{
                return minus ? -num : num;
            }
            b = readByte();
        }
    }
    
    private static long nl()
    {
        long num = 0;
        int b;
        boolean minus = false;
        while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
        if(b == '-'){
            minus = true;
            b = readByte();
        }
        
        while(true){
            if(b >= '0' && b <= '9'){
                num = num * 10 + (b - '0');
            }else{
                return minus ? -num : num;
            }
            b = readByte();
        }
    }
    
    private static void tr(Object... o) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}

Note: This problem (Bigger is Greater) is generated by HackerRank but the solution is provided by CodingBroz. This tutorial is only for Educational and Learning purpose.