/*
 * @lc app=leetcode id=20 lang=java
 *
 * [20] Valid Parentheses
 */

// @lc code=start

import java.util.Deque;

class Solution {
    public boolean isValid(String s) {
        int br_1_cnt = 0, br_2_cnt = 0, br_3_cnt = 0;
        Deque<Integer> op_type_stack = new ArrayDeque<Integer>();
        for(int i=0;i<s.length();i++) {
            char ch = s.charAt(i);
            if(isOpenBr(ch)) {
                int op_type = getOpenBrType(ch);
                op_type_stack.push(op_type);
                if(op_type == 1) {
                    br_1_cnt++;
                } else if(op_type == 2) {
                    br_2_cnt++;
                } else if(op_type == 3) {
                    br_3_cnt++;
                }
            } else {
                int close_type = getCloseBrType(ch);
                if(op_type_stack.isEmpty()) {
                    return false;
                } else if(op_type_stack.peek() != close_type) {
                    return false;
                }
                op_type_stack.pop();
                if(close_type == 1) {
                    br_1_cnt--;
                } else if(close_type == 2) {
                    br_2_cnt--;
                } else if(close_type == 3) {
                    br_3_cnt--;
                }
            }
        }
        return br_1_cnt == 0 && br_2_cnt == 0 && br_3_cnt == 0;
    }

    private boolean isOpenBr(char ch) {
        return ch == '(' || ch == '[' || ch == '{';
    }

    private int getOpenBrType(char ch) {
        switch(ch) {
            case '(':
                return 1;
            case '[':
                return 2;
            case '{':
                return 3;
            default:
                throw new RuntimeException("invalid open brack");
        }
    }

    private int getCloseBrType(char ch) {
        switch(ch) {
            case ')':
                return 1;
            case ']':
                return 2;
            case '}':
                return 3;
            default:
                throw new RuntimeException("invalid close brack");
        }
    }
}
// @lc code=end