保证一个单调栈,一旦发现有数据a小于栈顶,那么把栈中第一个大于等于a的数据替换成a
C++ 代码
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
const int N = 100010;
int n, a[N];
vector<int>stack;
int main()
{
cin >> n;
for(int i = 0; i < n; i++) cin >> a[i];
for(int i = 0; i < n; i++)
{
if(stack.empty() || stack.back() < a[i]) stack.push_back(a[i]);
else *lower_bound(stack.begin(), stack.end(), a[i]) = a[i];
}
cout << stack.size() << endl;
return 0;
}