De Shaw C - String

#include <bits/stdc++.h>
using namespace std;

int main() {
    // your code goes here

    // Ques input
    string str = "ababkeca";
    int k = 2;

    // Soln
    int left = 0, right = 0;
    int n = str.length();

    unordered_map<char, int> mp;
    bool flag = 1;
    int ans = k+1;

    while(left<n && right<n){
        if(flag){
            mp[str[right]]++;
        }

        vector<int> count(26, 0);
        for(int i=0; i<26; ++i){
            char a = 'a' + i;
            count[i] = mp[a];
        }

        sort(count.begin(), count.end());

        int maxi1 = count[25], maxi2 = count[24];
        int sum = accumulate(count.begin(), count.end(), 0);

        if(maxi1==0 || maxi2==0 || sum- maxi1 - maxi2<=k){
            ans = max(ans , right - left + 1);
            right++;
            flag = 1;
        }
        else if(sum- maxi1 - maxi2 > k){
            mp[str[left++]]--;
            flag = 0;
        }

    }

    cout<<ans<<endl;

    return 0;
}