UVa 673 - Parentheses Balance

673 - Parentheses Balance

思路：用stack从左到右处理字符串，同种括号出栈异种入栈

#include <cstdio>#include <cstring>#include <string>#include <iostream>#include <sstream>#include <cmath>#include <algorithm>#include <vector>#include <iomanip>#include <map>#include <set>#include <stack>using namespace std;char f(char c) {if (c == ')')return '(';if (c == ']')return '[';return 0;}bool judge(const string& s) {stack<char> st;st.push('0');for (int i = 0; i < s.size(); i++) {if (st.top() != f(s[i])) //与栈顶括号同种栈顶出栈，异种后者入栈st.push(s[i]);elsest.pop();}return st.size() == 1; //栈中只剩下'0'}int main(void) {int n;string s;while (cin >> n) {getchar();while (n--) {getline(cin, s);if (s.size() == 0 || judge(s))cout << "Yes" << endl;elsecout << "No" << endl;}}return 0;}