day08之元素出栈、入栈顺序的合法性+计算一个整数二进制位中1的个数

bool IsPopOrder(vector<int> pushV,vector<int> popV)
{
if(pushV.size() != popV.size())
return false;

stack<int> s;
int j = 0;
for(int i = 0; i < pushV.size(); ++i)
{
s.push(pushV[i]);

while( !s.empty() &&s.top() == popV[j])
{
s.pop();
j++;
}
}
return s.size() == 0;
}

int  NumberOf1(int n)
{
int num = 0;
while(n)
{
num++;
n = n & (n-1);
}
return num;
}