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+/*
+Challenge 194
+
+Task 2: Frequency Equalizer
+Submitted by: Mohammad S Anwar
+You are given a string made of alphabetic characters only, a-z.
+
+Write a script to determine whether removing only one character can make the
+frequency of the remaining characters the same.
+
+Example 1:
+Input: $s = 'abbc'
+Output: 1 since removing one alphabet 'b' will give us 'abc' where each
+alphabet frequency is the same.
+Example 2:
+Input: $s = 'xyzyyxz'
+Output: 1 since removing 'y' will give us 'xzyyxz'.
+Example 3:
+Input: $s = 'xzxz'
+Output: 0 since removing any one alphabet would not give us string with same
+frequency alphabet.
+*/
+
+#include <iostream>
+#include <string>
+#include <vector>
+#include <cctype>
+
+const int LETTERS = ('z'-'a'+1);
+
+int freq_equalizer(const std::string& s) {
+    std::vector<int> freq;
+    freq.resize(LETTERS);
+
+    if (s.empty()) return 0;
+    for (auto& c : s) {
+        if (isalpha(c))
+            freq[tolower(c)-'a']++;
+    }
+
+    int min=0, max=0;
+    for (auto& f : freq) {
+        if (f) {
+            if (min==0) min=max=f;
+            if (min>f) min=f;
+            if (max<f) max=f;
+        }
+    }
+
+    if (min+1!=max) return 0;
+
+    int count=0;
+    for (auto& f : freq) {
+        if (f==max) count++;
+    }
+
+    return count==1 ? 1 : 0;
+}
+
+int main(int argc, char* argv[]) {
+    argv++; argc--;
+    if (argc != 1) {
+        std::cerr << "usage: ch-1 string" << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    std::cout << freq_equalizer(argv[0]) << std::endl;
+}