Ultraviolet A 12657-boxes in a line (what is the difference between AC and TLE? Why is STL slow ..)

Written using the list in STL, TLE

#include<cstdio>#include<iostream>#include<cstring>#include<list>#include<algorithm>using namespace std;list<int> l;list<int>::iterator it1,it2,it3,it4,it5,it;void work(int a,int a1=1,int a2=1){    it1=find(l.begin(),l.end(),a1);    it2=find(l.begin(),l.end(),a2);    it3=find(l.begin(),l.end(),a2);    it4=find(l.begin(),l.end(),a1);    it5=find(l.begin(),l.end(),a2);    if(a==1)    {        if(*it4++==a2) return;        l.erase(it1);        l.insert(it2,a1);    }    if(a==2)    {        if(*it5++==a1) return;        l.erase(it1);        l.insert(++it3,a1);    }    if(a==3)    {        l.insert(it2,a1);        l.insert(it1,a2);        l.erase(it1);        l.erase(it2);    }    if(a==4)    {        l.reverse();    }}int main(){    int m,n;    int kk,x,y;    int kase=0;    while(cin>>n>>m)    {        kase++;        l.clear();        for(int i=1; i<=n; i++)            l.push_back(i);        for(int i=0;i<m;i++)        {            cin>>kk;            if(kk==4)                work(kk);            else            {                cin>>x>>y;                work(kk,x,y);            }        }        bool flag=true;        long long ans=0;        for(it=l.begin(); it!=l.end(); ++it)        {            if(flag)            {                ans+=*it;            }            flag=!flag;        }        cout<<"Case "<<kase<<": "<<ans<<endl;    }    return 0;}

AC code, simulate the linked list with Arrays:

#include<cstdio>#include<cstring>#include<iostream>using namespace std;const int maxn = 100010;int next[maxn],prev[maxn];void unlink(int pos1){    int temp1 = prev[pos1];    int temp2 = next[pos1];    next[temp1]=temp2;    prev[temp2]=temp1;}void link(int pos1,int pos2,int aa){    next[pos1]=aa;    next[aa]=pos2;    prev[pos2]=aa;    prev[aa]=pos1;}int main(){    int n,m;    int a,b,c;    int kase=0;    while(scanf("%d%d",&n,&m)!=EOF)    {        kase++;        memset(next,0,sizeof(next));        memset(prev,0,sizeof(prev));        for(int i=1; i<=n; i++)        {            next[i]=(i+1)%(n+1);            prev[i]=(i-1);        }        next[0]=1;        prev[0]=n;        bool flag=true;        for(int i=0; i<m; i++)        {            scanf("%d",&a);            if(a==1)            {                scanf("%d%d",&b,&c);                if(b==prev[c]) continue;                unlink(b);                if(flag)                    link(prev[c],c,b);                else                    link(c,next[c],b);            }            if(a==2)            {                scanf("%d%d",&b,&c);                if(b==next[c]) continue;                unlink(b);                if(flag)                    link(c,next[c],b);                else                    link(prev[c],c,b);            }            if(a==3)            {                scanf("%d%d",&b,&c);                if(next[b]==c)                {                    int temp1=prev[b];                    int temp2=next[c];                    prev[b]=c;                    next[c]=b;                    prev[c]=temp1;                    next[b]=temp2;                    next[temp1]=c;                    prev[temp2]=b;                }                else if(prev[b]==c)                {                    int temp1=prev[c];                    int temp2=next[b];                    prev[c]=b;                    next[b]=c;                    prev[b]=temp1;                    next[c]=temp2;                    next[temp1]=b;                    prev[temp2]=c;                }                else                {                    unlink(b);                    unlink(c);                    int temp1=prev[c];                    int temp2=next[c];                    link(prev[b],next[b],c);                    link(temp1,temp2,b);                }            }            if(a==4)            {                flag=!flag;            }        }        long long ans=0;        if(flag)        {            bool flag1=true;            for(int i=next[0]; i!=0; i=next[i])            {                if(flag1)                {                    ans+=i;                }                flag1=!flag1;            }        }        else        {            bool flag1=true;            for(int i=prev[0]; i!=0; i=prev[i])            {                if(flag1)                {                    ans+=i;                }                flag1=!flag1;            }        }        cout<<"Case "<<kase<<": "<<ans<<endl;    }    return 0;}

STL is convenient, but it is indeed much slower. Be cautious when using it...