首页 > 代码库 > POJ3903Stock Exchange&&POJ1631Bridging signals最长上升子序列 &&POJ1887Testing the CATCHER(最长下降子序列)(LIS模版题)

POJ3903Stock Exchange&&POJ1631Bridging signals最长上升子序列 &&POJ1887Testing the CATCHER(最长下降子序列)(LIS模版题)

题目链接:http://poj.org/problem?id=3903 

题目链接:http://poj.org/problem?id=1631

题目链接:http://poj.org/problem?id=1887

题目解析:

这两道题都是直接求最长上升子序列,没什么好说的。

POJ 3903这题n为1000000,如果用n^2的算法肯定超时,所以要选择nlogn的算法。都是简单题。

#include <iostream>#include <string.h>#include <stdio.h>#include <algorithm>#include <math.h>#define eps 1e-9using namespace std;int n,len,a[100010],d[100010];int er(int q[],int l,int r,int key)//好好研究二分{    int mid;    while(l<=r)    {        mid=(l+r)/2;        if(q[mid]==key)        {            return mid;        }        else if(q[mid]>key)        {            r=mid-1;        }        else l=mid+1;    }    return l;}int main(){    int we;    while(scanf("%d",&n)!=EOF)    {        for(int i=1; i<=n; i++)        {            scanf("%d",&a[i]);        }        len=1;        d[len]=a[1];        for(int i=2; i<=n; i++)        {            if(a[i]>d[len])            {                d[++len]=a[i];            }            else            {                we=er(d,1,len,a[i]);                d[we]=a[i];            }        }        printf("%d\n",len);    }    return 0;}

POJ1631:

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#include <iostream>#include <string.h>#include <stdio.h>#include <algorithm>#include <math.h>#define eps 1e-9using namespace std;int n,len,a[40010],d[40010];int er(int q[],int l,int r,int key)//好好研究二分{    int mid;    while(l<=r)    {        mid=(l+r)/2;        if(q[mid]==key)        {            return mid;        }        else if(q[mid]>key)        {            r=mid-1;        }        else l=mid+1;    }    return l;}int main(){    int we,T;    scanf("%d",&T);    while(T--)    {        scanf("%d",&n);        for(int i=1; i<=n; i++)        {            scanf("%d",&a[i]);        }        len=1;        d[len]=a[1];        for(int i=2; i<=n; i++)        {            if(a[i]>d[len])            {                d[++len]=a[i];            }            else            {                we=er(d,1,len,a[i]);                d[we]=a[i];            }        }        printf("%d\n",len);    }    return 0;}
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POJ1887Testing the CATCHER:

#include <iostream>#include <string.h>#include <stdio.h>#include <algorithm>#include <math.h>using namespace std;int n,a[40002],d[40002],len;int er(int q[],int l,int r,int key)//好好研究二分{    int mid;    while(l<=r)    {        mid=(l+r)/2;        if(q[mid]==key)        {            return mid;        }        else if(q[mid]>key)        {            r=mid-1;        }        else l=mid+1;    }    return l;}int main(){    int tt,we,K=0;    while(scanf("%d",&a[1])!=EOF&&a[1]!=-1)    {        tt=1;        while(scanf("%d",&a[++tt])!=EOF&&a[tt]!=-1)            ;        tt-=1;        len=1;        d[len]=a[tt];        for(int i=tt-1; i>=1; i--)        {            if(a[i]>d[len])            {                d[++len]=a[i];            }            else            {                we=er(d,1,len,a[i]);                d[we]=a[i];            }        }        printf("Test #%d:\n",++K);        printf("  maximum possible interceptions: %d\n\n",len);    }    return 0;}

 

POJ3903Stock Exchange&&POJ1631Bridging signals最长上升子序列 &&POJ1887Testing the CATCHER(最长下降子序列)(LIS模版题)