leetcode/100-n/523. 连续的子数组和.md

https://leetcode-cn.com/problems/continuous-subarray-sum/

class Solution {
    public boolean checkSubarraySum(int[] nums, int k) {
        int numLen = nums.length;
        if(numLen < 2){
            return false;
        }
        Map<Integer, Integer> map = new HashMap<Integer, Integer>();
        //用来计算为0的结果，-1表示最短为2才能返回true
        map.put(0, -1);
        int numsPreSum = 0;
        for(int i = 0; i < numLen; i++){
            numsPreSum = (numsPreSum + nums[i]) % k;
            if(map.containsKey(numsPreSum)){
                //距离大于等于2 由于是前缀和，所以要排除首位
                if(map.get(numsPreSum) + 2 <= i){
                    return true;
                }
            }else{
                map.put(numsPreSum, i);
            }
        }
        return false;
    }
}