HDU 4747 Mex

Mex

Time Limit: 15000/5000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)
Total Submission(s): 1414    Accepted Submission(s): 464


Problem Description
Mex is a function on a set of integers, which is universally used for impartial game theorem. For a non-negative integer set S, mex(S) is defined as the least non-negative integer which is not appeared in S. Now our problem is about mex function on a sequence.

Consider a sequence of non-negative integers {ai}, we define mex(L,R) as the least non-negative integer which is not appeared in the continuous subsequence from aL to aR, inclusive. Now we want to calculate the sum of mex(L,R) for all 1 <= L <= R <= n.
 

Input
The input contains at most 20 test cases.
For each test case, the first line contains one integer n, denoting the length of sequence.
The next line contains n non-integers separated by space, denoting the sequence.
(1 <= n <= 200000, 0 <= ai <= 10^9)
The input ends with n = 0.
 

Output
For each test case, output one line containing a integer denoting the answer.
 

Sample Input
  
3 0 1 3 5 1 0 2 0 1 0
 

Sample Output
  
5 24
Hint
For the first test case: mex(1,1)=1, mex(1,2)=2, mex(1,3)=2, mex(2,2)=0, mex(2,3)=0,mex(3,3)=0. 1 + 2 + 2 + 0 +0 +0 = 5.
 

Source
 

Recommend
liuyiding
   
        这题真是做了很长时间啊,但是还是没有过,代码已经出来了,自几测试了上百组数据都过了,交上去就是wa,求数据啊,求数据,求数据,急切的求数据。
终于发现错误了,其实三四天前的代码,只要改一下输出就对了,用long long ,要用cout,否则会错,三四天前的代码如果改成cout<<ans<<endl; 就过了,只不过那时候我怀疑用map映射的时候,映射10^9 ,会出错,就没有向输出考虑,于是就把代码改了,改的时候忽略了一个问题,我把大于200000的没有加到数组中,当时只是以为大于200000的没用,其实还是很有用的,我没仔细想想,就以为他一点用没有,导致这三四天来,反复的改代码都wa。哎,慎重,一定要慎重啊!

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#define N 200010
#define INF 0x7ffffff
using namespace std;
struct num
{
    int l,r;
    __int64 col,Max,sum;
}a[4*N];
int pt[N],b[N],tag[N],pos1,pos2;
int q[N];
int main()
{
    //freopen("data.in","r",stdin);
    //freopen("data1.out","w",stdout);
    void build(int k,int l,int r);
    void del(int k,int val);
    void find(int k,int val);
    void update(int k,int l,int r,int val);
    int n;
    while(scanf("%d",&n)!=EOF)
    {
        if(n==0)
        {
            break;
        }
        int Top=1;
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&b[Top]);
            if(b[Top]<=200000)            //错误之处
            {
                Top++;
            }
        }
        n = Top-1;
        if(n==0)
        {
            printf("0\n");
            continue;
        }
        memset(q,0,sizeof(q));
        int res = 0;
        __int64 ans=0;
        for(int i=1;i<=n;i++)
        {
            q[b[i]]=1;
            while(q[res]!=0)
            {
                res++;
            }
            tag[i] = res;
            ans+=(__int64)res;
        }
        memset(pt,0,sizeof(pt));
        memset(q,0,sizeof(q));
        for(int i=1;i<=n;i++)
        {
            int x=b[i];
            if(q[x]!=0)
            {
                pt[q[x]]=i;
            }
            q[x]=i;
        }
        build(1,1,n);
        for(int i=1;i<=n;i++)
        {
            del(1,i);
            pos1 = INF;
            int val=b[i];
            if(a[1].Max<val)
            {
                ans+=a[1].sum;
                continue;
            }
            find(1,val);
            pos2 = pt[i]-1;
            if(pos2 ==-1)
            {
                pos2 = n;
            }
            if(pos1>pos2)
            {
                ans+=a[1].sum;
                continue;
            }
            update(1,pos1,pos2,val);
            ans+=a[1].sum;
        }
      cout<<ans<<endl;
    }
    return 0;
}
void pushup(int k)
{
    a[k].Max = max(a[k<<1].Max,a[k<<1|1].Max);
    a[k].sum = a[k<<1].sum+a[k<<1|1].sum;
    a[k].col= 1;
}
void build(int k,int l,int r)
{
    a[k].l = l;
    a[k].r = r;
    if(l==r)
    {
        a[k].sum = tag[l];
        a[k].Max = tag[l];
        a[k].col = 0;
        return;
    }
    int mid = (l+r)>>1;
    build(k<<1,l,mid);
    build(k<<1|1,mid+1,r);
    pushup(k);
}
void del(int k,int val)
{
    if(a[k].l==a[k].r)
    {
        a[k].col=0;
        a[k].sum=0;
        return ;
    }
    if(a[k].col==0)
    {
        a[k<<1].col=0;
        a[k<<1].Max = a[k].Max;
        a[k<<1].sum = a[k].Max*(__int64)(a[k<<1].r-a[k<<1].l+1);
        a[k<<1|1].col=0;
        a[k<<1|1].Max = a[k].Max;
        a[k<<1|1].sum = a[k].Max*(__int64)(a[k<<1|1].r-a[k<<1|1].l+1);
    }
    int mid = (a[k].l+a[k].r)>>1;
    if(mid>=val)
    {
        del(k<<1,val);
    }else
    {
        del(k<<1|1,val);
    }
    pushup(k);
}
void find(int k,int val)
{
    if(a[k].col==0&&a[k].Max>val)
    {
        pos1 = a[k].l;
        return ;
    }
    if(a[k].col==0)
    {
        return;
    }
    if(a[k].l==a[k].r&&a[k].Max>val)
    {
        pos1 = a[k].l;
        return ;
    }
    if(a[k<<1].Max>val)
    {
        find(k<<1,val);
    }else if(a[k<<1|1].Max>val)
    {
        find(k<<1|1,val);
    }
}
void update(int k,int l,int r,int val)
{
    if(a[k].l==l&&a[k].r==r)
    {
        a[k].Max = val;
        a[k].sum = (__int64)(a[k].r -a[k].l + 1)*(__int64)val;
        a[k].col=0;
        return ;
    }
    if(a[k].col==0)
    {
        a[k<<1].col=0;
        a[k<<1].Max = a[k].Max;
        a[k<<1].sum = a[k].Max*(__int64)(a[k<<1].r-a[k<<1].l+1);
        a[k<<1|1].col=0;
        a[k<<1|1].Max = a[k].Max;
        a[k<<1|1].sum = a[k].Max*(__int64)(a[k<<1|1].r-a[k<<1|1].l+1);
    }
    int mid = (a[k].l+a[k].r)>>1;
    if(r<=mid)
    {
        update(k<<1,l,r,val);
    }else if(l>mid)
    {
        update(k<<1|1,l,r,val);
    }else
    {
        update(k<<1,l,mid,val);
        update(k<<1|1,mid+1,r,val);
    }
    pushup(k);
}
AC的代码:
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#define N 200010
#define INF 0x7ffffff
using namespace std;
struct num
{
    int l,r;
    __int64 col,Max,sum;
}a[4*N];
int pt[N],b[N],tag[N],pos1,pos2;
int q[N];
int main()
{
    //freopen("data.in","r",stdin);
    //freopen("data1.out","w",stdout);
    void build(int k,int l,int r);
    void del(int k,int val);
    void find(int k,int val);
    void update(int k,int l,int r,int val);
    int n;
    while(scanf("%d",&n)!=EOF)
    {
        if(n==0)
        {
            break;
        }
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&b[i]);
        }
        memset(q,0,sizeof(q));
        int res = 0;
        __int64 ans=0;
        for(int i=1;i<=n;i++)
        {
            if(b[i]<=200000)
            {
                q[b[i]]=1;
            }
            while(q[res]!=0)
            {
                res++;
            }
            tag[i] = res;
            ans+=(__int64)res;
        }
        memset(pt,0,sizeof(pt));
        memset(q,0,sizeof(q));
        for(int i=1;i<=n;i++)
        {
            int x=b[i];
            if(x>200000)
            {
                continue;
            }
            if(q[x]!=0)
            {
                pt[q[x]]=i;
            }
            q[x]=i;
        }
        build(1,1,n);
        for(int i=1;i<=n;i++)
        {
            del(1,i);
            pos1 = INF;
            int val=b[i];
            if(a[1].Max<val)
            {
                ans+=a[1].sum;
                continue;
            }
            find(1,val);
            pos2 = pt[i]-1;
            if(pos2 ==-1)
            {
                pos2 = n;
            }
            if(pos1>pos2)
            {
                ans+=a[1].sum;
                continue;
            }
            update(1,pos1,pos2,val);
            ans+=a[1].sum;
        }
      cout<<ans<<endl;
    }
    return 0;
}
void pushup(int k)
{
    a[k].Max = max(a[k<<1].Max,a[k<<1|1].Max);
    a[k].sum = a[k<<1].sum+a[k<<1|1].sum;
    a[k].col= 1;
}
void build(int k,int l,int r)
{
    a[k].l = l;
    a[k].r = r;
    if(l==r)
    {
        a[k].sum = tag[l];
        a[k].Max = tag[l];
        a[k].col = 0;
        return;
    }
    int mid = (l+r)>>1;
    build(k<<1,l,mid);
    build(k<<1|1,mid+1,r);
    pushup(k);
}
void del(int k,int val)
{
    if(a[k].l==a[k].r)
    {
        a[k].col=0;
        a[k].sum=0;
        return ;
    }
    if(a[k].col==0)
    {
        a[k<<1].col=0;
        a[k<<1].Max = a[k].Max;
        a[k<<1].sum = a[k].Max*(__int64)(a[k<<1].r-a[k<<1].l+1);
        a[k<<1|1].col=0;
        a[k<<1|1].Max = a[k].Max;
        a[k<<1|1].sum = a[k].Max*(__int64)(a[k<<1|1].r-a[k<<1|1].l+1);
    }
    int mid = (a[k].l+a[k].r)>>1;
    if(mid>=val)
    {
        del(k<<1,val);
    }else
    {
        del(k<<1|1,val);
    }
    pushup(k);
}
void find(int k,int val)
{
    if(a[k].col==0&&a[k].Max>val)
    {
        pos1 = a[k].l;
        return ;
    }
    if(a[k].col==0)
    {
        return;
    }
    if(a[k].l==a[k].r&&a[k].Max>val)
    {
        pos1 = a[k].l;
        return ;
    }
    if(a[k<<1].Max>val)
    {
        find(k<<1,val);
    }else if(a[k<<1|1].Max>val)
    {
        find(k<<1|1,val);
    }
}
void update(int k,int l,int r,int val)
{
    if(a[k].l==l&&a[k].r==r)
    {
        a[k].Max = val;
        a[k].sum = (__int64)(a[k].r -a[k].l + 1)*(__int64)val;
        a[k].col=0;
        return ;
    }
    if(a[k].col==0)
    {
        a[k<<1].col=0;
        a[k<<1].Max = a[k].Max;
        a[k<<1].sum = a[k].Max*(__int64)(a[k<<1].r-a[k<<1].l+1);
        a[k<<1|1].col=0;
        a[k<<1|1].Max = a[k].Max;
        a[k<<1|1].sum = a[k].Max*(__int64)(a[k<<1|1].r-a[k<<1|1].l+1);
    }
    int mid = (a[k].l+a[k].r)>>1;
    if(r<=mid)
    {
        update(k<<1,l,r,val);
    }else if(l>mid)
    {
        update(k<<1|1,l,r,val);
    }else
    {
        update(k<<1,l,mid,val);
        update(k<<1|1,mid+1,r,val);
    }
    pushup(k);
}

三四天前改后AC的代码:
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <map>
#define N 200010
using namespace std;
struct num
{
    long long int l,r,color,Max,sum;
}a[5*N];
map<int,int>q;
int pt[N],b[N],tag[N],pos1,pos2;
int main()
{
    //freopen("data.in","r",stdin);
    void build(int k,int l,int r);
    void del(int k,int val);
    void find(int k,int val);
    void update(int k,int l,int r,int val);
    int n;
    while(scanf("%d",&n)!=EOF)
    {
        if(n==0)
        {
            break;
        }
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&b[i]);
        }
        q.clear();
        int res = 0;
        long long int ans=0;
        for(int i=1;i<=n;i++)
        {
            q[b[i]]=1;
            while(q[res]!=0)
            {
                res++;
            }
            tag[i] = res;
            ans+=(long long int)res;
        }
        q.clear();
        memset(pt,0,sizeof(pt));
        for(int i=1;i<=n;i++)
        {
            int x=b[i];
            if(q[x]!=0)
            {
                pt[q[x]]=i;
            }
            q[x]=i;
        }
        build(1,1,n);
        for(int i=1;i<=n;i++)
        {
            del(1,i);
            int val=b[i];
            find(1,val);
            pos2 = pt[i]-1;
            if(pos2 ==-1)
            {
                pos2 = n;
            }
            if(pos1>pos2||a[1].Max<val)
            {
                ans+=a[1].sum;
                continue;
            }
            update(1,pos1,pos2,val);
            ans+=a[1].sum;
        }
       cout<<ans<<endl;
    }
    return 0;
}
void pushup(int k)
{
    a[k].Max = max(a[k<<1].Max,a[k<<1|1].Max);
    a[k].sum = a[k<<1].sum+a[k<<1|1].sum;
    a[k].color = 1;
}
void build(int k,int l,int r)
{
    a[k].l = l;
    a[k].r = r;
    if(l==r)
    {
        a[k].sum = tag[l];
        a[k].Max = tag[l];
        a[k].color = 0;
        return;
    }
    int mid = (l+r)>>1;
    build(k<<1,l,mid);
    build(k<<1|1,mid+1,r);
    pushup(k);
}
void del(int k,int val)
{
    if(a[k].l==a[k].r)
    {
        a[k].color=0;
        a[k].sum=0;
        return ;
    }
    if(a[k].color==0)
    {
        a[k<<1].color=0;
        a[k<<1].Max = a[k].Max;
        a[k<<1].sum = a[k].Max*(long long int)(a[k<<1].r-a[k<<1].l+1);
        a[k<<1|1].color=0;
        a[k<<1|1].Max = a[k].Max;
        a[k<<1|1].sum = a[k].Max*(long long int)(a[k<<1|1].r-a[k<<1|1].l+1);
    }
    int mid = (a[k].l+a[k].r)>>1;
    if(mid>=val)
    {
        del(k<<1,val);
    }else
    {
        del(k<<1|1,val);
    }
    pushup(k);
}
void find(int k,int val)
{
    if(a[k].color==0&&a[k].Max>val)
    {
        pos1 = a[k].l;
        return ;
    }
    if(a[k].color==0)
    {
        return;
    }
    if(a[k].l==a[k].r&&a[k].Max>val)
    {
        pos1 = a[k].l;
        return ;
    }
    if(a[k<<1].Max>val)
    {
        find(k<<1,val);
    }else if(a[k<<1|1].Max>val)
    {
        find(k<<1|1,val);
    }
}
void update(int k,int l,int r,int val)
{
    if(a[k].l==l&&a[k].r==r)
    {
        a[k].Max = val;
        a[k].sum = (a[k].r -a[k].l + 1)*val;
        a[k].color=0;
        return ;
    }
    if(a[k].color==0)
    {
        a[k<<1].color=0;
        a[k<<1].Max = a[k].Max;
        a[k<<1].sum = a[k].Max*(a[k<<1].r-a[k<<1].l+1);
        a[k<<1|1].color=0;
        a[k<<1|1].Max = a[k].Max;
        a[k<<1|1].sum = a[k].Max*(a[k<<1|1].r-a[k<<1|1].l+1);
    }
    int mid = (a[k].l+a[k].r)>>1;
    if(r<=mid)
    {
        update(k<<1,l,r,val);
    }else if(l>mid)
    {
        update(k<<1|1,l,r,val);
    }else
    {
        update(k<<1,l,mid,val);
        update(k<<1|1,mid+1,r,val);
    }
    pushup(k);
}



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