GFG Count all possible paths from top left to bottom right

SPACE OPTIMIZED SOLUTION

class Solution {
  public:
    long long int numberOfPaths(int m, int n){
        vector<long long> curr(n,0);
        vector<long long> prev(n,1);
        
        int mod=1e9+7;
        
        curr[0]=1;
        
       
       for(int i=1;i<m;i++)
       {
           for(int j=1;j<n;j++)
           {
               curr[j]=((curr[j-1]%mod)+ (prev[j]%mod))%mod;
           }
           prev=curr;
       }
       
       return prev[n-1];
       
        
    }
};