1983. Widest Pair of Indices With Equal Range Sum

You are given two 0-indexed binary arrays nums1 and nums2. Find the widest pair of indices (i, j) such that i <= j and nums1[i] + nums1[i+1] + … + nums1[j] == nums2[i] + nums2[i+1] + … + nums2[j].

The widest pair of indices is the pair with the largest distance between i and j. The distance between a pair of indices is defined as j - i + 1.

Return the distance of the widest pair of indices. If no pair of indices meets the conditions, return 0.

class Solution {
public:
    int widestPairOfIndices(vector<int>& A, vector<int>& B) {
        int res = 0, n = A.size();
        unordered_map<int, int> mp;
        mp[0] = {-1};
        for(int i = 0, sum = 0; i < n; i++) {
            sum += A[i] - B[i];
            if(mp.count(sum)) res = max(res, i - mp[sum]);
            else mp[sum] = i;
        }
        return res;
    }
};