HDU 1423 Greatest Common Increasing Subsequence

最长公共上升子序列。

O(n*n*n)

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<iostream>
using namespace std;
typedef long long LL;
const double pi=acos(-1.0),eps=1e-8;
void File()
{
    freopen("D:\in.txt","r",stdin);
    freopen("D:\out.txt","w",stdout);
}
inline int read()
{
    char c = getchar();  while(!isdigit(c)) c = getchar();
    int x = 0;
    while(isdigit(c)) { x = x * 10 + c - '0'; c = getchar(); }
    return x;
}

const int maxn=550;
int dp[maxn][maxn];
int T,ans,len1,len2,a[maxn],b[maxn];

int main()
{
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d",&len1); for(int i=1;i<=len1;i++) scanf("%d",&a[i]);
        scanf("%d",&len2); for(int i=1;i<=len2;i++) scanf("%d",&b[i]);
        memset(dp,ans=0,sizeof dp);
        for(int i=1;i<=len1;i++)
        {
            for(int j=1;j<=len2;j++)
            {
                if(a[i]!=b[j]) dp[i][j]=dp[i-1][j];
                else
                {
                    for(int s=0;s<=j-1;s++)
                    {
                        if(b[s]>=b[j]) continue;
                        dp[i][j]=max(dp[i][j],dp[i-1][s]+1);
                    }
                }
                ans=max(ans,dp[i][j]);
            }
        }
        printf("%d
",ans);
        if(T>0) printf("
");
    }
    return 0;
}

优化后O(n*n)

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<iostream>
using namespace std;
typedef long long LL;
const double pi=acos(-1.0),eps=1e-8;
void File()
{
    freopen("D:\in.txt","r",stdin);
    freopen("D:\out.txt","w",stdout);
}
inline int read()
{
    char c = getchar();  while(!isdigit(c)) c = getchar();
    int x = 0;
    while(isdigit(c)) { x = x * 10 + c - '0'; c = getchar(); }
    return x;
}

const int maxn=550;
int dp[maxn][maxn],f[maxn][maxn];
int T,ans,len1,len2,a[maxn],b[maxn];

int main()
{
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d",&len1); for(int i=1;i<=len1;i++) scanf("%d",&a[i]);
        scanf("%d",&len2); for(int i=1;i<=len2;i++) scanf("%d",&b[i]);
        memset(dp,ans=0,sizeof dp); memset(f,0,sizeof f);
        for(int i=1;i<=len1;i++)
        {
            int MAX=0;
            for(int j=1;j<=len2;j++)
            {
                if(a[i]!=b[j]) dp[i][j]=dp[i-1][j]; else dp[i][j]=MAX+1;
                if(a[i]>b[j]) MAX=max(MAX,dp[i][j]); ans=max(ans,dp[i][j]);
            }
        }
        printf("%d
",ans); if(T) printf("
");
    }
    return 0;
}