[bzoj3226][Sdoi2008]校门外的区间——线段树

题目

略

题解

直接套黄学长模板。
Orz

代码

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define inf 1000000000
#define n (65536 * 2 + 1)
char ch[5];
int read() {
  int x = 0, f = 0;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '(')
      f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  if (ch == ')')
    f = 1;
  return x * 2 - f;
}
struct seg {
  int l, r, val, tag, rev;
} t[4 * n];

void build(int k, int l, int r) {
  t[k].l = l;
  t[k].r = r;
  t[k].tag = -1;
  if (l == r)
    return;
  int mid = (l + r) >> 1;
  build(k << 1, l, mid);
  build(k << 1 | 1, mid + 1, r);
}

void pushdown(int k) {
  int tag = t[k].tag, rev = t[k].rev;
  t[k].tag = -1;
  t[k].rev = 0;
  if (t[k].l == t[k].r) {
    if (tag != -1)
      t[k].val = tag;
    t[k].val ^= rev;
    return;
  }
  if (tag != -1) {
    t[k << 1].tag = t[k << 1 | 1].tag = tag;
    t[k << 1].rev = t[k << 1 | 1].rev = 0;
  }
  t[k << 1].rev ^= rev;
  t[k << 1 | 1].rev ^= rev;
}
int query(int k, int x) {
  pushdown(k);
  int l = t[k].l, r = t[k].r;
  if (l == r)
    return t[k].val;
  int mid = (l + r) >> 1;
  if (x <= mid)
    return query(k << 1, x);
  else
    return query(k << 1 | 1, x);
}
void modify(int k, int x, int y, int val) {
  if (y < x)
    return;
  pushdown(k);
  int l = t[k].l, r = t[k].r;
  if (l == x && r == y) {
    if (val == -1)
      t[k].rev ^= 1;
    else
      t[k].tag = val;
    return;
  }
  int mid = (l + r) >> 1;
  if (y <= mid)
    modify(k << 1, x, y, val);
  else if (x > mid)
    modify(k << 1 | 1, x, y, val);
  else {
    modify(k << 1, x, mid, val);
    modify(k << 1 | 1, mid + 1, y, val);
  }
}
void rever(int k, int x, int y) { modify(k, x, y, -1); }
int main() {
  build(1, 1, n);
  while (scanf("%s", ch) != EOF) {
    int a = read(), b = read();
    a += 2;
    b += 2;
    switch (ch[0]) {
    case 'U':
      modify(1, a, b, 1);
      break;
    case 'I':
      modify(1, 1, a - 1, 0);
      modify(1, b + 1, n, 0);
      break;
    case 'D':
      modify(1, a, b, 0);
      break;
    case 'C':
      modify(1, 1, a - 1, 0);
      modify(1, b + 1, n, 0);
      rever(1, a, b);
      break;
    case 'S':
      rever(1, a, b);
      break;
    }
  }
  int start = -1, last = -1, flag = 0;
  for (int i = 1; i <= n; i++) {
    if (query(1, i)) {
      if (start == -1)
        start = i;
      last = i;
    } else {
      if (start != -1) {
        if (flag)
          printf(" ");
        else
          flag = 1;
        if (start & 1)
          printf("(");
        else
          printf("[");
        printf("%d", start / 2 - 1);
        printf(",");
        printf("%d", (last + 1) / 2 - 1);
        if (last & 1)
          printf(")");
        else
          printf("]");
      }
      last = start = -1;
    }
  }
  if (!flag)
    printf("empty set");
  return 0;
}