Count number of substrings with numeric value greater than X - GeeksforGeeks

25 May, 2021
Given a string ‘S’ (composed of digits) and an integer ‘X”, the task is to count all the sub-strings of ‘S’ that satisfy the following conditions:  
The sub-string must not begin with the digit ‘0’.
And the numeric number it represents must be greater than ‘X’.
Note: Two ways of selecting a sub-string are different if they begin or end at different indices.
Examples:  
Input: S = "471", X = 47
Output: 2
Only the sub-strings "471" and "71" 
satisfy the given conditions.

Input: S = "2222", X = 97
Output: 3
Valid strings are "222", "222" and "2222". 
Approach:  
Iterate over each digit of the string ‘S’ and choose the digits which are greater than ‘0’.
Now, take all possible sub-strings starting from the character chosen in the previous step and convert each sub-string to an integer.
Compare the integer from the previous step to ‘X’. If the number is greater than ‘X’, then increment the count variable.
Finally, print the value of the count variable.
Below is the implementation of the above approach:  
C++
Java
Python3
C#
PHP
Javascript
// C++ implementation of the approach#include <bits/stdc++.h>using namespace std; // Function that counts// valid sub-stringsint count(string S, int X){    int count = 0;    const int N = S.length();    for (int i = 0; i < N; ++i) {         // Only take those numbers        // that do not start with '0'.        if (S[i] != '0') {            for (int len = 1; (i + len) <= N; ++len) {                 // converting the sub-string                // starting from index 'i'                // and having length 'len' to int                // and checking if it is greater                // than X or not                if (stoi(S.substr(i, len)) > X)                    count++;            }        }    }    return count;} // Driver codeint main(){     string S = "2222";    int X = 97;    cout << count(S, X);     return 0;}
// Java implementation of the approachimport java.util.*; class GFG{// Function that counts// valid sub-stringsstatic int count(String S, int X){    int count = 0;    int N = S.length();    for (int i = 0; i < N; ++i)    {         // Only take those numbers        // that do not start with '0'.        if (S.charAt(i) != '0')        {            for (int len = 1;                (i + len) <= N; ++len)            {                 // converting the sub-string                // starting from index 'i'                // and having length 'len' to                // int and checking if it is                // greater than X or not                int num = Integer.parseInt(S.substring(i, i + len));                if (num > X)                    count++;            }        }    }    return count;} // Driver codepublic static void main(String []args){    String S = "2222";    int X = 97;    System.out.println(count(S, X));}} // This code is contributed by ihritik
# Python3 implementation of# the approach # Function that counts# valid sub-stringsdef countSubStr(S, X):     cnt = 0    N = len(S)         for i in range(0, N):         # Only take those numbers        # that do not start with '0'.        if (S[i] != '0'):                         j = 1            while((j + i) <= N):                 # converting the sub-string                # starting from index 'i'                # and having length 'len' to                # int and checking if it is                # greater than X or not                num = int(S[i : i + j])                             if (num > X):                    cnt = cnt + 1                                 j = j + 1             return cnt; # Driver codeS = "2222";X = 97;print(countSubStr(S, X)) # This code is contributed by ihritik
// C# implementation of the approachusing System; class GFG{// Function that counts// valid sub-stringsstatic int count(string S, int X){    int count = 0;    int N = S.Length;    for (int i = 0; i < N; ++i)    {         // Only take those numbers        // that do not start with '0'.        if (S[i] != '0')        {            for (int len = 1;                (i + len) <= N; ++len)            {                 // converting the sub-string                // starting from index 'i'                // and having length 'len' to int                // and checking if it is greater                // than X or not                int num = Int32.Parse(S.Substring(i, len));                if (num > X)                    count++;            }        }    }    return count;} // Driver codepublic static void Main(String []args){    string S = "2222";    int X = 97;    Console.WriteLine(count(S, X));}} // This code is contributed by ihritik
<?php// PHP implementation of the approach // Function that counts// valid sub-stringsfunction countSubStr($S, $X){    $cnt = 0;    $N = strlen($S);         for ($i = 0; $i < $N; ++$i)    {         // Only take those numbers        // that do not start w$ith '0'.        if ($S[$i] != '0')        {            for ($len = 1;                ($i + $len) <= $N; ++$len)            {                 // converting the sub-str$ing                // starting from index 'i'                // and having length 'len' to int                // and checking if it is greater                // than X or not                $num = intval(substr($S, $i, $len));                             if ($num > $X)                    $cnt++;            }        }    }    return $cnt;} // Driver code$S = "2222";$X = 97;echo countSubStr($S, $X); // This code is contributed by ihritik?>
<script> // Javascript implementation of the approach // Function that counts// valid sub-stringsfunction count(S, X){    var count = 0;    var N = S.length;    for (var i = 0; i < N; ++i) {         // Only take those numbers        // that do not start with '0'.        if (S[i] != '0') {            for (var len = 1; (i + len) <= N; ++len) {                 // converting the sub-string                // starting from index 'i'                // and having length 'len' to int                // and checking if it is greater                // than X or not                if (parseInt(S.substring(i, i+len)) > X)                    count++;            }        }    }    return count;} // Driver codevar S = "2222";var X = 97;document.write( count(S, X)); </script>
3
 
ihritik
importantly
substring
Competitive Programming
Mathematical
Strings
Strings
Mathematical
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Top 15 Websites for Coding Challenges and Competitions
Breadth First Traversal ( BFS ) on a 2D array
Shortest path in a directed graph by Dijkstra’s algorithm
Runtime Errors
Multistage Graph (Shortest Path)
Program for Fibonacci numbers
Write a program to print all permutations of a given string
C++ Data Types
Set in C++ Standard Template Library (STL)
Coin Change | DP-7