#include <bits/stdc++.h>
using namespace std;
long long comb(int n, int r) {
    if (r > n) return 0;
    if (r == 0 || r == n) return 1;
    long long res = 1;
    for (int i = 0; i < r; i++) {
        res = res * (n - i) / (i + 1);
    }
    return res;
}
long long Balanced(int A, int B, int C) {
    long long s = 0;
    for (int p = 4; p <= min(A, C - 1); p++) {
    int w = C - p; 
    if (w >= 1 && w <= B) { 
    s += comb(A, p) * comb(B, w);
        }
    }
    return s;
} // Balance Mixture

✅

#include <iostream>
#include <string>
#include <cmath>
using namespace std;
int gap(char a, char b) {
    return abs(a - b);
}
string longestKInterspaceSubstring( string &word, int k) {
    string temp = "", maxSubstring = "";
    for (size_t i = 0; i < word.length(); i++) {
    temp += word[i];
    if (i < word.length() - 1 && gap(word[i], word[i + 1]) > k) {
    if (temp.length() > maxSubstring.length()) {
    maxSubstring = temp;
    }
    temp = "";
        }
    }
    if (temp.length() > maxSubstring.length()) {
        maxSubstring = temp;
    }

    return maxSubstring;
}

Longest K intersapace substring ✅
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