904. Fruit Into Baskets

Link

Solution

   public int totalFruit(int[] tree) {
        int n = tree.length;
        int[] counts = new int[n];
        int start = 0, end = 0, typeCount = 0, ret = 0;
        while(end < n){
            int num = tree[end];
            counts[num]++;
            if(counts[num] == 1){
                typeCount++;
            }
            while(typeCount > 2){
                int startNum = tree[start];
                counts[startNum]--;
                if(counts[startNum] == 0){
                    typeCount--;
                }
                start++;
            }
            ret = Math.max(ret, end - start + 1);
            end++;
        }
        return ret;
    }