力扣2762. 不间断子数组

力扣2762. 不间断子数组

multiset法

• multiset：元素从小到大排序

  • begin()返回头指针 (最小)
  • rbegin()返回尾指针 (最大)

  class Solution {
  public:
      long long continuousSubarrays(vector<int>& nums) {
          int n = nums.size();
          long long res = 0;
          multiset<int> s;
          for(int i=0,j=0;i<n;i++)
          {   
              s.insert(nums[i]);
              while(*s.rbegin() - *s.begin() > 2)
              {
                  s.erase(s.find(nums[j++]));
              }
              res += i-j+1;
          }
          return res;
      }
  };

哈希表法

• map：记录出现次数

  • 同样的rbegin和begin

  class Solution {
  public:
      long long continuousSubarrays(vector<int>& nums) {
          int n = nums.size();
          long long res = 0;
          map<int,int> cnt;
          for(int i=0,j=0;i<n;i++)
          {   
              cnt[nums[i]] ++;
              while(cnt.rbegin()->first - cnt.begin()->first > 2)
              {
                  if(-- cnt[nums[j]] == 0) cnt.erase(nums[j++]);
              }
              res += i-j+1;
          }
          return res;
      }
  };