leetcode

2337.cpp (566B)

 class Solution {
   public:
     bool canChange(const string &start, const string &target) const {
         const int n = size(start);
         int i = 0, j = 0;
 
         while (i < n || j < n) {
             while (i < n && start[i] == '_')
                 i++;
             while (j < n && target[j] == '_')
                 j++;
 
             if (i == n || j == n) return i == n && j == n;
 
             if (start[i] != target[j]) return false;
             if (start[i] == 'R' ? i > j : i < j) return false;
 
             i++, j++;
         }
 
         return true;
     }
 };