BZOJ3236 [Ahoi2013]作业

昨天晚上做的。。。差错一直查到今天= =

最后没办法问管理员要了数据才知道原来ans数组开小了233，简直沙茶

这道题不就是裸的莫队嘛= =|||

只要用树状数组维护当前的两种个数即可。

/**************************************************************
Problem: 3236
User: rausen
Language: C++
Result: Accepted
Time:79318 ms
Memory:66252 kb
****************************************************************/

#include <cstdio>
#include <cmath>
#include <algorithm>

#define lowbit(x) x & -x
using namespace std;
const int N = 100005;
const int M = 1000005;
const int Maxlen = 37000005;

int n, size, Q;
int BIT[2]
, cnt
, pos
, a
;
int ans1[M], ans2[M];
int Len, Left;
char buf[Maxlen];

struct Query {
int l, r, a, b, w;
} q[M];
inline bool operator < (const Query &a, const Query &b) {
return pos[a.l] == pos[b.l] ? a.r < b.r : pos[a.l] < pos[b.l];
}
inline bool cmp_id (const Query &a, const Query &b) {
return a.w < b.w;
}

inline int read() {
int x = 0;
while (buf[Left] < '0' || '9' < buf[Left])
++Left;
while ('0' <= buf[Left] && buf[Left] <= '9')
x = x * 10 + buf[Left++] - '0';
return x;
}

int len = 0, pr[15];
inline void print(int x) {
while (x)
pr[++len] = x % 10, x /= 10;
if (!len) putchar('0');
while (len)
putchar(pr[len--] + '0');
}

inline void update(int x, int del, int T) {
while (x <= n)
BIT[T][x] += del, x += lowbit(x);
}

inline int query(int x, int T) {
int res = 0;
while (x)
res += BIT[T][x], x -= lowbit(x);
return res;
}

inline void update(int x, int del) {
if (!cnt[x])
update(x, 1, 1);
cnt[x] += del;
if (!cnt[x])
update(x, -1, 1);
update(x, del, 0);
}

int main() {
int i, l, r;
Len = fread(buf, 1, Maxlen, stdin);
buf[Len] = ' ';
n = read(), Q = read();
size = (int) sqrt(n);
for (i = 1; i <= n; ++i)
a[i] = read(), pos[i] = i / size;
for (i = 1; i <= Q; ++i) {
q[i].l = read(), q[i].r = read();
q[i].a = read(), q[i].b = read();
q[i].w = i;
}

sort(q + 1, q + Q + 1);
for (i = l = 1, r = 0; i <= Q; ++i) {
for (; r < q[i].r; ) update(a[++r], 1);
for (; r > q[i].r; ) update(a[r--], -1);
for (; l < q[i].l; ) update(a[l++], -1);
for (; l > q[i].l; ) update(a[--l], 1);
ans1[q[i].w] = query(q[i].b, 0) - query(q[i].a - 1, 0);
ans2[q[i].w] = query(q[i].b, 1) - query(q[i].a - 1, 1);
}
for (i = 1; i <= Q; ++i) {
print(ans1[i]), putchar(' ');
print(ans2[i]), putchar('\r'), putchar('\n');
}
return 0;
}

View Code
（p.s. 这道题Rank 1的5 sec是怎么做到的= =，蒟蒻可是用了80 sec啊！！！）