49 lines
1.4 KiB
C++
49 lines
1.4 KiB
C++
#include <bits/stdc++.h>
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using namespace std;
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#define lowbit(x) (x & -x)
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const int N = 1e5 + 10;
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int n, a[N];
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//树状数组
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int tr[N];
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//离散化数组，提供指定值对应的排名,辅助树状数组
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vector<int> b;
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int res; //结果
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//计算x值在原序列中的排名
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int get(int x) {
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return lower_bound(b.begin(), b.end(), x) - b.begin() + 1;
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}
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//求tr[1]~tr[i]的最大值
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int query(int i) {
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int s = 0;
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for (; i; i -= lowbit(i)) s = max(s, tr[i]);
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return s;
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}
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//单点更新x
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void update(int i, int x) {
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for (; i <= n; i += lowbit(i)) tr[i] = max(tr[i], x); //注意这里是跳着取max,不是传统的sum求和
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}
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int main() {
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scanf("%d", &n);
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for (int i = 1; i <= n; i++) {
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scanf("%d", &a[i]);
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b.push_back(a[i]);
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}
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//离散化,用于存储a数组按值由小到大去重排序的结果，这样就可以使用二分查找 值->排名
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sort(b.begin(), b.end());
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b.erase(unique(b.begin(), b.end()), b.end());
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for (int i = 1; i <= n; i++) { //按原输入序进行遍历，这样才符合LIS的要求
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int k = get(a[i]); //获取值a[i]的整体大小排名k
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int t = query(k - 1) + 1; //在树状数组中查找排名为k-1的最大数量，再加1才是当前连接上后的数量
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update(k, t); //将排名k更新目前最优解t
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}
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//输出
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printf("%d\n", query(b.size()));
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return 0;
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} |