Minimum Insertions to Balance a Parentheses String LeetCode solution in Java

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class Solution {
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  public int minInsertions(String s) {
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    int open = 0;
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    int ans = 0;
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    for (int i = 0; i < s.length(); i++) {
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      if (s.charAt(i) == '(') {
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        open++;
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      } else {
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        if (i + 1 < s.length() && s.charAt(i + 1) == ')') {
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          i++;
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          if (open > 0) {
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            open--;
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          } else {
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            ans++;
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          }
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        } else {
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          if (open > 0) {
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            open--;
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            ans++;
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          } else {
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            ans += 2;
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          }
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        }
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      }
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    }
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    ans += 2 * open;
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    return ans;
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  }
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}