PAT L2-014 列车调度（Dilworth定理）

分析

AC代码：

#include <iostream>
#include <cmath>
#include <cstring>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
const int maxn = 1e5 + 100;
const int inf = 999999999;
int dp[maxn], a[maxn];
int main()
{
#ifdef LOCAL
//freopen("L2-014(Dilworth).in","r",stdin);
//freopen("L2-014(Dilworth).out","w",stdout);
#endif
int n;
while(cin >> n)
{
int len = 0;
memset(dp, 0, sizeof(dp));
for(int i = 0; i < n; i++)
{
int x;
cin >> x;
if(len == 0 || x >= dp[len-1]) dp[len++] = x;
else
{
int l = 0, r = len - 1;
while(l <= r)
{
int mid = (l+r)/2;
if(dp[mid] <= x) l = mid+1;
else r = mid - 1;
}
dp[l] = min(dp[l], x);
}
}
cout << len << endl;
}
return 0;
}