Minimum Number of Frogs Croaking in C++

C++Server Side ProgrammingProgramming

Suppose we have a string called croakOfFrogs, this represents a combination of the string "croak" from different frogs, multiple frogs can croak at the same time, so multiple "croak" are mixed. We have to find the minimum number of different frogs to finish all the croak in the given string.

Here a valid "croak" means a frog is generating 5 letters ‘c’, ’r’, ’o’, ’a’, ’k’ sequentially. The frogs have to generate all five letters to finish a croak. If the string is not a valid "croak" string then return -1.

So, if the input is like "crcoakroak", then the output will be 2 as the first frog could yell "crcoakroak". The second frog could yell later "crcoakroak".

To solve this, we will follow these steps −

  • Define one map m

  • Define an array ch of size: 5 assign it with {'c', 'r', 'o', 'a', 'k'}

  • temp := 0, ret := 0

  • for each element c in s, do

    • (increase m[c] by 1)

    • maxVal := m[ch[0]]

    • for initialize i := 0, when i < 5, update (increase i by 1), do −

      • if maxVal < m[ch[i]] or m[ch[i]] < 0, then −

        • return -1

      • maxVal := m[ch[i]]

    • if c is same as 'c', then −

      • (increase temp by 1)

    • otherwise when c is same as 'k', then −

      • (decrease temp by 1)

    • ret := maximum of ret and temp

  • for initialize i := 1, when i < 5, update (increase i by 1), do −

    • if m[ch[0]] is not equal to m[ch[i]], then −

      • return -1

  • return ret

Example 

Let us see the following implementation to get better understanding −

 Live Demo

#include <bits/stdc++.h>
using namespace std;
class Solution {
public:
   int minNumberOfFrogs(string s) {
      map<char, int> m;
      char ch[5] = { 'c', 'r', 'o', 'a', 'k' };
      int temp = 0;
      int ret = 0;
      for (auto& c : s) {
         m[c]++;
         int maxVal = m[ch[0]];
         for (int i = 0; i < 5; i++) {
            if (maxVal < m[ch[i]] || m[ch[i]] < 0) {
               return -1;
            }
            maxVal = m[ch[i]];
         }
         if (c == 'c') {
            temp++;
         }
         else if (c == 'k') {
            temp--;
         }
         ret = max(ret, temp);
      }
      for (int i = 1; i < 5; i++) {
         if (m[ch[0]] != m[ch[i]])
            return -1;
      }
      return ret;
   }
};
main(){
   Solution ob;
   cout << (ob.minNumberOfFrogs("crcoakroak"));
}

Input

"crcoakroak"

Output

2
raja
Updated on 17-Nov-2020 12:03:01

Advertisements