无重复最长字串 class Solution { public: int lengthOfLongestSubstring(string s) { if(s.size() == 0) return 0; unordered_set<char> lookup; int maxStr = 0; int left = 0; for(int i = 0; i < s.size(); i++){ while (lookup.find(s[i]) != lookup.end()){ lookup.erase(s[left]); left ++; } maxStr = max(maxStr,i-left+1); lookup.insert(s[i]); } return maxStr; } }; 最大连续1的个数 class Solution { public: int longestOnes(vector<int>& A, int K) { int res = 0, zeros = 0, left = 0; for (int right = 0; right < A.size(); ++right) { if (A[right] == 0) ++zeros; while (zeros > K) { if (A[left++] == 0) --zeros; } res = max(res, right - left + 1); } return res; } };