fix north_east_lattice_paths.hpp

Author: hitonanode

other_algorithms/north_east_lattice_paths.hpp

@@ -181,6 +181,9 @@ NorthEastLatticePathsBothBounded(const std::vector<int> &lb, const std::vector<i
     std::vector<MODINT> dp_left = left;
     std::vector<int> tmp_ub;
     while (true) {
+        if (x + 1 < n and lb[x + 1] >= ub[x]) {
+            return std::vector<MODINT>(ub.back() - lb.back());
+        }
         dp_left.resize(ub[x] - lb[x], MODINT{0});
 
         const int x1 = std::upper_bound(ub.begin() + x + 1, ub.begin() + n, ub[x]) - ub.begin();