Question

我试图解决有效的括号，并且如标题所述，我无法确定Array.push如何在此上下文中工作。

＆＃13;

function isValidPar(par){
  var stack = [];
  var length = par.length;
  
  for (var i=0; i<length; i++) {
    var p = par[i];
    if(p === "(" || p === "{" || p === "[") {
      stack.push(p);
    } else if(p === ")") {
        if(stack.length === 0 || stack[stack.length-1] != "(") {return false}
          stack.pop();
      } else if(p === "]") {
          if(stack.length === 0 || stack[stack.length-1] != "[") {return false}
            stack.pop();
      } else if(p === "}") {
          if(stack.length === 0 || stack[stack.length-1] != "{") {return false}
            stack.pop();
    } return stack.length === 0;
  }
}

＆＃13;

如果console.log在stack.push()之后，那么它会显示我刚刚插入的元素。但是当我在其他任何地方尝试它时，比如在else if语句内部或在return之前，似乎数组是空的。

Answer 1

以下是您的代码的更正版本

＆＃13;

function isValidPar(par){
  var stack = [];
  var length = par.length;
  
  for (var i=0; i<length; i++) {
    var p = par[i];
    if(p === "(" || p === "{" || p === "[") {
      stack.push(p);
    } else if(p === ")") {
        if(stack.length === 0 || stack[stack.length-1] != "(") {return false}
          stack.pop();
      } else if(p === "]") {
          if(stack.length === 0 || stack[stack.length-1] != "[") {return false}
            stack.pop();
      } else if(p === "}") {
          if(stack.length === 0 || stack[stack.length-1] != "{") {return false}
            stack.pop();
    } 
  }
  return stack.length === 0;
}

console.log(isValidPar('(())'));

＆＃13;

return stack.length === 0;

一旦for循环结束，应该检查

JavaScript .push到空数组无效

1 个答案: