学步园

多说几句话，省的摘要里都是没格式的代码。。。

线段树的单点更新。

模板题。

重新整理了一下 0.0

#include <stdio.h>
#define N (50005)
#define LSON (idx << 1)
#define RSON ((idx << 1) | 1)
#define MID ((l + r) >> 1)

int tree[N << 2];

void build (int l, int r, int idx)
{
  if (l == r)
  {
    scanf ("%d", &tree[idx]);
    return ;
  }
  build (l, MID, LSON);
  build (MID + 1, r, RSON);
  tree[idx] = tree[LSON] + tree[RSON];
}

int query (int L, int R, int l, int r, int idx)
{
  if (L <= l && r <= R)
    return tree[idx];
  if (MID + 1 > R)
    return query(L, R, l, MID, LSON);
  if (MID < L)
    return query (L, R, MID + 1, r, RSON);
  int a = query (L, R, l, MID, LSON);
  int b = query (L, R, MID + 1, r, RSON);
  return a + b;
}

void update (int A, int del, int l, int r, int idx)
{
  if (r < A || A < l) return;
  if (l == r)
  {
    if (l == A)
      tree[idx] += del;
    return;
  }
  update (A, del, l, MID, LSON);
  update (A, del, MID + 1, r, RSON);
  tree[idx] = tree[LSON] + tree[RSON];
}

int main()
{
  int n_case;
  scanf ("%d", &n_case);
  for (int i_case = 1; i_case <= n_case; i_case++)
  {
    int n;
    scanf ("%d", &n);
    build (1, n, 1);
    printf ("Case %d:\n", i_case);
    for (char in[10]; ; )
    {
      scanf ("%s", in);
      switch (in[0])
      {
      case 'Q':
        {
          int l, r;
          scanf ("%d%d", &l, &r);
          printf ("%d\n", query (l, r, 1, n, 1));
        } break;
      case 'E':
        break;
      case 'A':
        {
          int a, add;
          scanf ("%d%d", &a, &add);
          update (a, add, 1, n, 1);
        } break;
      case 'S':
        {
          int a, sub;
          scanf ("%d%d", &a, &sub);
          update (a, -sub, 1, n, 1);
        } break;
      default:
        break;
      }
    }
  }
  return 0;
}