1865. 找出和为指定值的下标对

,5,4

class FindSumPairs:
    def __init__(self, nums1: List[int], nums2: List[int]):
        self.nums1 = nums1
        self.nums2 = nums2
        self.counter = Counter(nums2)

    def add(self, index: int, val: int) -> None:
        old_val = self.nums2[index]
        self.counter[old_val] -= 1
        self.nums2[index] += val
        self.counter[old_val + val] += 1

    def count(self, tot: int) -> int:
        return sum([self.counter[tot - num] for num in self.nums1])


# Your FindSumPairs object will be instantiated and called as such:
# obj = FindSumPairs(nums1, nums2)
# obj.add(index,val)
# param_2 = obj.count(tot)

class FindSumPairs {
    private int[] nums1;
    private int[] nums2;
    private Map<Integer, Integer> counter;

    public FindSumPairs(int[] nums1, int[] nums2) {
        this.nums1 = nums1;
        this.nums2 = nums2;
        counter = new HashMap<>();
        for (int num : nums2) {
            counter.put(num, counter.getOrDefault(num, 0) + 1);
        }
    }

    public void add(int index, int val) {
        int oldVal = nums2[index];
        counter.put(oldVal, counter.get(oldVal) - 1);
        nums2[index] += val;
        counter.put(oldVal + val, counter.getOrDefault(oldVal + val, 0) + 1);
    }

    public int count(int tot) {
        int res = 0;
        for (int num : nums1) {
            res += counter.getOrDefault(tot - num, 0);
        }
        return res;
    }
}

/**
 * Your FindSumPairs object will be instantiated and called as such:
 * FindSumPairs obj = new FindSumPairs(nums1, nums2);
 * obj.add(index,val);
 * int param_2 = obj.count(tot);
 */