{
   "question_id": 20,
   "question_title": "有效的括号",
   "difficulty": "简单",
   "question_content": "<p>给定一个只包括 <code>'('</code>，<code>')'</code>，<code>'{'</code>，<code>'}'</code>，<code>'['</code>，<code>']'</code> 的字符串 <code>s</code> ，判断字符串是否有效。</p><p>有效字符串需满足：</p><ol>\t<li>左括号必须用相同类型的右括号闭合。</li>\t<li>左括号必须以正确的顺序闭合。</li></ol><p> </p><p><strong>示例 1：</strong></p><pre><strong>输入：</strong>s = \"()\"<strong><br />输出：</strong>true</pre><p><strong>示例 2：</strong></p><pre><strong>输入：</strong>s = \"()[]{}\"<strong><br />输出：</strong>true</pre><p><strong>示例 3：</strong></p><pre><strong>输入：</strong>s = \"(]\"<strong><br />输出：</strong>false</pre><p><strong>示例 4：</strong></p><pre><strong>输入：</strong>s = \"([)]\"<strong><br />输出：</strong>false</pre><p><strong>示例 5：</strong></p><pre><strong>输入：</strong>s = \"{[]}\"<strong><br />输出：</strong>true</pre><p> </p><p><strong>提示：</strong></p><ul>\t<li><code>1 <= s.length <= 10<sup>4</sup></code></li>\t<li><code>s</code> 仅由括号 <code>'()[]{}'</code> 组成</li></ul>",
   "topic_link": "https://bbs.csdn.net/topics/600470114",
   "cpp": "#include <stack>\nchar ascii_tab[128];\nclass Solution\n{\npublic:\n\tbool isValid(string s)\n\t{\n\t\tif (s.size() == 0)\n\t\t\treturn true;\n\t\tstd::stack<char> st;\n\t\tascii_tab['('] = 11;\n\t\tascii_tab['{'] = 12;\n\t\tascii_tab['['] = 13;\n\t\tascii_tab[')'] = 21;\n\t\tascii_tab['}'] = 22;\n\t\tascii_tab[']'] = 23;\n\t\tfor (auto c : s)\n\t\t{\n\t\t\tchar n = ascii_tab[c];\n\t\t\tif (n < 20)\n\t\t\t\tst.push(n);\n\t\t\telse\n\t\t\t{\n\t\t\t\tif (st.empty())\n\t\t\t\t\treturn false;\n\t\t\t\tif (n != st.top() + 10)\n\t\t\t\t\treturn false;\n\t\t\t\tst.pop();\n\t\t\t}\n\t\t}\n\t\tif (st.empty())\n\t\t\treturn true;\n\t\treturn false;\n\t}\n};",
   "java": "class Solution {\n\tpublic boolean isValid(String s) {\n\t\tchar[] parentheses = { '(', '[', '{', ')', ']', '}' };\n\t\tint i = 0;\n\t\tchar c;\n\t\tint[] sum = { 0, 0, 0 };\n\t\tStack<Integer> top = new Stack<Integer>();\n\t\twhile (i < s.length()) {\n\t\t\tc = s.charAt(i);\n\t\t\tfor (int j = 0; j <= 2; j++) {\n\t\t\t\tif (c == parentheses[j]) {\n\t\t\t\t\ttop.push(j);\n\t\t\t\t\tsum[j]++;\n\t\t\t\t} else if (c == parentheses[j + 3]) {\n\t\t\t\t\tif (top.size() == 0 || top.peek() != j) {\n\t\t\t\t\t\treturn false;\n\t\t\t\t\t}\n\t\t\t\t\ttop.pop();\n\t\t\t\t\tsum[j]--;\n\t\t\t\t} else {\n\t\t\t\t}\n\t\t\t}\n\t\t\ti++;\n\t\t}\n\t\tfor (int j = 0; j <= 2; j++) {\n\t\t\tif (sum[j] != 0) {\n\t\t\t\treturn false;\n\t\t\t}\n\t\t}\n\t\treturn true;\n\t}\n}",
   "js": "/**\n * @param {string} s\n * @return {boolean}\n */\nvar isValid = function(s) {\n   \tlet parentheses = [\n   \t\t'(', '[', '{', \n   \t\t')', ']', '}'\n   \t];\n   \tlet i=0;\n   \tlet c;\n   \tlet sum = [0,0,0]\n   \tlet top = [];\n   \twhile(i<s.length){\n       \tc = s[i];\n       \tfor(let j=0;j<=2;j++){\n           \tif(c===parentheses[j]){\n           \t\ttop.push(j);\n           \t\tsum[j]++;\n           \t}else if(c===parentheses[j+3]){\n           \t\tif(top[top.length-1]!==j){\n           \t\t\treturn false;\t\n           \t\t}\n           \t\ttop.pop();\n           \t\tsum[j]--;\n           \t}else {\n\n           \t}\n       \t}\n       \ti++;\n   \t} \n\n   \tfor(let j=0;j<=2;j++){\n   \t\tif(sum[j]!==0){\n   \t\t\treturn false;\n   \t\t}\n   \t}\n   \treturn true;\n};\n\nfunction main(){\n\tconst testCases = [\n\t\t[\"()\",true],\n\t\t[\"()[]{}\",true],\n\t\t[\"(]\",false],\n\t\t[\"([)]\",false],\n\t\t[\"{[]}\",true]\n\t];\n\tfor(const testCase of testCases){\n\t\tconst v = isValid(testCase[0]);\n\t\tif(v===testCase[1]){\n\t\t\tconsole.log(`[OK]`);\n\t\t}else{\n\t\t\tconsole.log(`[ERROR]`);\n\t\t}\n\t}\n}\n\nmain();\n",
   "python": "class Solution:\n\tdef isValid(self, s: str) -> bool:\n\t\tparentheses = [\n\t\t\t'(', '[', '{',\n\t\t\t')', ']', '}'\n\t\t]\n\t\ti = 0\n\t\tsum = [0, 0, 0]\n\t\ttop = []\n\t\twhile i < len(s):\n\t\t\tc = s[i]\n\t\t\tj = 0\n\t\t\twhile j <= 2:\n\t\t\t\tif c == parentheses[j]:\n\t\t\t\t\ttop.append(j)\n\t\t\t\t\tsum[j] += 1\n\t\t\t\telif c == parentheses[j+3]:\n\t\t\t\t\tif len(top) == 0 or top[len(top)-1] != j:\n\t\t\t\t\t\treturn False\n\t\t\t\t\ttop.pop()\n\t\t\t\t\tsum[j] -= 1\n\t\t\t\tj += 1\n\t\t\ti += 1\n\t\tif sum[0] != 0 or sum[1] != 0 or sum[2] != 0:\n\t\t\treturn False\n\t\telse:\n\t\t\treturn True\n# %%\ns = Solution()\nprint(s.isValid(s = \"()[]{}\"))",
   "status": 1,
   "keywords": "栈,字符串",
   "license": {
      "cpp": "csdn.net",
      "python": "csdn.net",
      "java": "csdn.net"
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