[leetcode] 992. Subarrays with K Different Integers : https://leetcode.com/problems/subarrays-with-k-different-integers/ 투 포인터

Subarrays with K Different Integers.cpp

class Solution {
    
public:
    int subarraysWithKDistinct(vector<int>& A, int K) {
        
        int l = 0;
        vector<int> cnt(A.size()+1, 0);
        int diffCnt = 0;
        int answer = 0;
        int tmpAns = 0;
        
        for(int r=0;r<A.size();r++){
            int now = A[r];
            if(cnt[now] == 0){ // new
                // erase diff
                if(diffCnt == K){
                    while(l<r) {
                        cnt[A[l]]--;
                        l++;
                        if(cnt[A[l-1]] == 0)
                            break;
                    }
                    tmpAns = 0;
                }else{
                    diffCnt++;
                }
            }
            
            cnt[now]++;
            
            if(diffCnt == K){
                while(l<r){
                    if(cnt[A[l]] == 1) break;
                    cnt[A[l]]--;
                    l++;
                    tmpAns++;
                }
                answer += tmpAns + 1;
            }
            
        }
        
        return answer;
    }
};