hdu 4348 To the moon

题意：n个数 m次操作
操作分别为
C l r d: 把区间[l, r] 加 d
Q l r : 查询区间[l, r]的和
H l r t: 查询时间t的时候[l, r]的和
B t: 回到时间t

思路：主席树区间修改，区间求和

 const int maxn =  + ;
 const int maxnode =  * maxn;

 int n, m;

 struct Node
 {
     int l, r;
     LL sum, add;
 } tr[maxnode];
 int tail;
 LL a[maxn];
 LL qL, qR, value;
 LL sum;

 #define lson tr[o].l,L,M
 #define rson tr[o].r,M+1,R
 #define self o,L,R
 #define lc tr[o].l
 #define rc tr[o].r

 void build(int o, int L, int R)
 {
     if (L == R)
     {
         tr[o].sum = a[L];
         return;
     }
     tr[o].l = ++tail;
     tr[o].r = ++tail;
     int M = L + (R - L) / ;
     build(lson);
     build(rson);
     tr[o].sum = tr[lc].sum + tr[rc].sum;
 }

 void maintain(int o, int L, int R)
 {
     if (L < R)
     {
         tr[o].sum = tr[lc].sum + tr[rc].sum;
     }
     else tr[o].sum = a[L];
     tr[o].sum += tr[o].add * (R - L + );
 }

 void update(int& o, int L, int R)
 {
     tr[++tail] = tr[o];
     o = tail;
     if (qL <= L && R <= qR)
     {
         tr[o].add += value;
     }
     else
     {
         int M = L + (R - L) / ;
         if (qL <= M) update(lson);
         if (qR > M) update(rson);
     }
     maintain(self);
 }

 void query(int o, int L, int R, int add)
 {
     if (qL <= L && R <= qR)
     {
         sum += tr[o].sum + add * (R - L + );
         return;
     }
     int M = L + (R - L) / ;
     if (qL <= M) query(lson, add + tr[o].add);
     if (qR > M)  query(rson, add + tr[o].add);
 }

 int root[maxn];//表示第i个线段树的root是什么，显然root[0]=0

 void init()
 {
     memset(tr, , sizeof(tr));
     tail = ;
     for (int i = ; i <= n; i++)
     {
         scanf("%lld", &a[i]);
     }
     root[] = ;
     build(, , n);
 }

 void solve()
 {
     char op[];
     int t;
     int i = ;
     while (m--)
     {
         op[] = ;
         scanf("%s", op);
         if (op[] == 'Q')
         {
             scanf("%lld%lld", &qL, &qR);
             sum = ;
             query(root[i], , n, );
             printf("%lld\n", sum);

         }
         else if (op[] == 'C')
         {
             i++;
             root[i] = root[i-];
             scanf("%lld%lld%lld", &qL, &qR, &value);
             update(root[i], , n);
         }
         else if (op[] == 'H')
         {
             scanf("%lld%lld%d", &qL, &qR, &t);
             sum = ;
             query(root[t], , n, );
             printf("%lld\n", sum);
         }
         else
         {
             scanf("%d", &t);
             i = t;
         }
     }
 }

 int main()
 {
     while (scanf("%d%d", &n, &m) == )
     {
         init();
         solve();
     }
     return ;
 }