leetcode

0 class Solution {

1 public:

2 int findMaxLength(const vector<int> &nums) const {

3 unordered_map<int, int> um;

4 int res = 0, sum = 0;

5

6 um.emplace(0, -1);

7 for (int i = 0; i < size(nums); i++) {

8 sum += nums[i] ? 1 : -1;

9 auto it = um.find(sum);

10 if (it != end(um))

11 res = max(res, i - it->second);

12 else

13 um.emplace(sum, i);

14 }

15

16 return res;

17 }

18 };