Guest User

Untitled

a guest
Feb 20th, 2016
166
Never
Not a member of Pastebin yet? Sign Up, it unlocks many cool features!
  1. #include <bits/stdc++.h>
  2. #define endl "\n"
  3. using namespace std;
  4.  
  5. const int MOD = 1000000007;
  6.  
  7. int n,m,k;
  8. char a[1<<17];
  9. bool vis[2044][5111][2];
  10. int dp_ans[2044][5111][2];
  11. int s[1<<17],min_s;
  12.  
  13. int get_dp(int pos, int sum, bool f) {
  14. if(sum>2000 || sum<0) return 0;
  15. if(pos>k) {
  16. if(f==false) {
  17. if(sum+min_s>=0 && sum+s[m]==0) return 1;
  18. else return 0;
  19. }
  20. else {
  21. if(sum==0) return 1;
  22. else return 0;
  23. }
  24. }
  25. if(vis[pos][sum][f]) return dp_ans[pos][sum][f];
  26. int ans=0;
  27. ans=(ans+get_dp(pos+1,sum+1,f))%MOD;//Open
  28. ans=(ans+get_dp(pos+1,sum-1,f))%MOD;//Close
  29. if(f==false) {
  30. if(sum+min_s>=0) ans=(ans+get_dp(pos,sum+s[m],1))%MOD;//Skip;
  31. }
  32. vis[pos][sum][f]=true;
  33. dp_ans[pos][sum][f]=ans;
  34. return ans;
  35. }
  36.  
  37. int main() {
  38. cin.tie(NULL);
  39. ios::sync_with_stdio(0);
  40. int i;
  41.  
  42. cin>>n>>m;
  43. k=n-m;
  44. cin>>(a+1);
  45. for(i=1;i<=m;i++) if(a[i]=='(') s[i]=1; else s[i]=-1;
  46. for(i=1;i<=m;i++) s[i]+=s[i-1];
  47. min_s=1000000000;
  48. for(i=1;i<=m;i++) min_s=min(min_s,s[i]);
  49. cout<<get_dp(1,0,0)<<endl;
  50.  
  51. return 0;
  52. }
RAW Paste Data

Adblocker detected! Please consider disabling it...

We've detected AdBlock Plus or some other adblocking software preventing Pastebin.com from fully loading.

We don't have any obnoxious sound, or popup ads, we actively block these annoying types of ads!

Please add Pastebin.com to your ad blocker whitelist or disable your adblocking software.

×