# Minimum String in C++

Suppose we have two strings s and t of same length, and both are in lowercase letters. Consider we have rearranged s at first into any order, then count the minimum number of changes needed to turn s into t.

So, if the input is like s = "eccynue", t = "science", then the output will be 2 as if we rearrange "eccynue" to "yccence", then replace y with s and second c with i, it will be "science".

To solve this, we will follow these steps −

• ret := 0

• Define two arrays cnt1 to hold frequency of s and cnt2 to hold frequency of t

• for initialize i := 0, when i < 26, update (increase i by 1), do −

• ret := ret + max(cnt1[i] - cnt2[i], 0)

• return ret

Let us see the following implementation to get better understanding −

## Example

Live Demo

#include <bits/stdc++.h>
using namespace std;
class Solution {
public:
int solve(string s, string t) {
int ret = 0;
vector <int> cnt1(26);
vector <int> cnt2(26);
for(int i = 0; i < s.size(); i++){
cnt1[s[i] - 'a']++;
}
for(int i = 0; i < t.size(); i++){
cnt2[t[i] - 'a']++;
}
for(int i = 0; i < 26; i++){
ret += max(cnt1[i] - cnt2[i], 0);
}
return ret;
}
};
int main(){
Solution ob;
cout << (ob.solve("eccynue", "science"));
}

## Input

"eccynue", "science"

## Output

2

Updated on: 02-Sep-2020

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