HDU 4699 Editor 维护栈

维护两个栈,分别存光标前和光标后的数

再维护前缀和的栈 和 前缀和最大值的栈

注意一下左移,右移,删除到顶了就不操作了

5个操作

I x : 光标处插入x  -----> s1.push(x)

D  : 光标前删除    -----> s1.pop()

L  :  光标左移      -----> s2.push(s1.top())   s1.pop()

R  :  光标右移      -----> s1.push(s2.top())   s2.pop()

Q k : 输出前k个数前缀和最大值

/********************* Template ************************/
#include <set>
#include <map>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <cstdio>
#include <string>
#include <vector>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <fstream>
#include <numeric>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <functional>
using namespace std;

#define EPS         1e-8
#define MAXN        1000050
#define MOD         (int)1e9+7
#define PI          acos(-1.0)
#define DINF        (1e10)
#define LINF        ((1LL)<<50)
#define INF         (0x3f3f3f3f)
#define max(a,b)    ((a) > (b) ? (a) : (b))
#define min(a,b)    ((a) < (b) ? (a) : (b))
#define max3(a,b,c) (max(max(a,b),c))
#define min3(a,b,c) (min(min(a,b),c))
#define BUG         cout<<"BUG! "<<endl
#define line        cout<<"--------------"<<endl
#define L(t)        (t << 1)
#define R(t)        (t << 1 | 1)
#define Mid(a,b)    ((a + b) >> 1)
#define lowbit(a)   (a & -a)
#define FIN         freopen("in.txt","r",stdin)
#define FOUT        freopen("out.txt","w",stdout)
#pragma comment     (linker,"/STACK:102400000,102400000")

// typedef long long LL;
// typedef unsigned long long ULL;
// typedef __int64 LL;
// typedef unisigned __int64 ULL;
// LL gcd(LL a,LL b){ return b?gcd(b,a%b):a; }
// LL lcm(LL a,LL b){ return a*b/gcd(a,b); }

/*********************   F   ************************/
int pstack[MAXN],sstack[MAXN];
int pre[MAXN];
int pmax[MAXN];
int main()
{
    //FIN;
    //FOUT;
    int n ;
    while(~scanf("%d",&n)){
        int now1 = 0,now2 = 0;
        while(n--){
            char ch;
            int a;
            getchar();
            scanf("%c",&ch);
            if(ch == 'I'){
                scanf("%d",&a);
                pstack[now1] = a;
                pre[now1] = (now1 == 0) ? a : (pre[now1-1]+a);
                pmax[now1] = (now1 == 0) ? a : max(pmax[now1-1],pre[now1]);
                now1++;
            }else if(ch == 'D'){
                if(now1 == 0) continue;
                now1--;
            }else if(ch == 'L'){
                if(now1 == 0) continue;
                sstack[now2] = pstack[now1-1];
                now1--;
                now2++;
            }else if(ch == 'R'){
                if(now2 == 0) continue;
                pstack[now1] = sstack[now2-1];
                pre[now1] = (now1 == 0) ? sstack[now2-1] : (pre[now1-1]+sstack[now2-1]);
                pmax[now1] = (now1 == 0) ? sstack[now2-1] : max(pmax[now1-1],pre[now1]);
                now2--;
                now1++;
            }else if(ch == 'Q'){
                scanf("%d",&a);
                printf("%d
",pmax[a-1]);
            }
        }
    }
    return 0;
}