挑战练习题2.3动态规划 poj1631 Bridging signals 最长递增子序列

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题目链接:

http://poj.org/problem?id=1631

题意:

直接看样例，题意是啥？

题解:

LIS， O(nlogn)的，维护一个数组ans，手动模拟一下就懂了。

代码:

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;typedef long long ll;#define MS(a) memset(a,0,sizeof(a))#define MP make_pair#define PB push_backconst int INF = 0x3f3f3f3f;const ll INFLL = 0x3f3f3f3f3f3f3f3fLL;inline ll read(){    ll x=0,f=1;char ch=getchar();    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}    return x*f;}//////////////////////////////////////////////////////////////////////////const int maxn = 1e5+10;int a[maxn],ans[maxn];int main(){    int T = read();    while(T--){        int n = read();        for(int i=1; i<=n; i++)            a[i] = read();        memset(ans,0x3f,sizeof(ans));        int mx = -1;        for(int i=1; i<=n; i++){            int p = lower_bound(ans+1,ans+1+n,a[i])-ans;            ans[p] = a[i];            mx = max(mx,p);        }        cout << mx << endl;    }    return 0;}

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