Day 125: Task Scheduler.cpp

int leastInterval(int N, int k, vector<char> &tasks) {
        // code here
        
         int counter[26] = {0};
    int maxF = 0; // max_freq
    int maxFc = 0; // no of ch having max_freq
    
    for (int i = 0; i < N; i++) {
        counter[tasks[i] - 'A']++;
    }
    
    for (int x : counter) {
        if (maxF == x) {
            maxFc++;
        }
        if (maxF < x) {
            maxF = x;
            maxFc = 1;
        }
    }
    
    int gaps = maxF - 1; // number of gaps required
    
    int gaps_len = k - (maxFc - 1); // number of ch that can be fit in partition gaps
    
    int avail_slot = gaps * gaps_len; // empty slots = number of gaps * gaps_len
    
    int avail_task = N - maxF * maxFc;
    
    int idles = max(0, avail_slot - avail_task); // place available tasks in total available
    // slots and rest as idle
    
    return N + idles;
    
    }