【字符串】856. 括号的分数

 1 class Solution {
 2 public:
 3     int scoreOfParentheses(string S) 
 4     {
 5         stack<int> stack;
 6         stack.push(0); // The score of the current frame
 7 
 8         for (int i = 0; i < S.size(); i++) 
 9         {
10             char c = S[i];
11             if (c == ‘(‘)
12                 stack.push(0);
13             else 
14             {
15                 int v = stack.top();
16                 stack.pop();
17                 int w = stack.top();
18                 stack.pop();
19                 stack.push(w + std::max(2 * v, 1));
20             }
21         }
22 
23         return stack.top();
24     }
25 };

 1 class Solution {
 2 
 3     public int scoreOfParentheses(String S) {
 4         int ans = 0, bal = 0;
 5         for (int i = 0; i < S.length(); ++i) {
 6             if (S.charAt(i) == ‘(‘) {
 7                 bal++;
 8             } else {
 9                 bal--;
10                 if (S.charAt(i-1) == ‘(‘)
11                     ans += 1 << bal;
12             }
13         }
14 
15         return ans;
16     }
17 };