找到牛

只有在后腿前面的前腿才能匹配上

C++

#include<string>
using namespace std;
int main()
{
  string s;
  cin >> s;
  int n = 0, ans = 0;
  for(int i = 0; i < s.size() - 1; i ++)
  {
        if(s[i]=='(' && s[i] == s[i + 1])n ++;
        if(s[i] == ')' && s[i] ==  s[i + 1])ans += n;
  }
  cout << ans <<endl;
  return 0;
}

JAVA

import java.util.*;
public class Main{
    public static void main(String[] args)
    {
        Scanner cin = new Scanner(System.in);
        String s = cin.nextLine();
        int a = 0, ans = 0;
        for(int i = 0; i < s.length() - 1; i ++)
        {
            if(s.charAt(i) == '(' && s.charAt(i) == s.charAt(i + 1))a ++;
            if(s.charAt(i) == ')' && s.charAt(i) == s.charAt(i + 1))ans += a;
        }
        System.out.println(ans);
    }
}