Created
December 30, 2018 19:59
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inline int h_bit(unsigned long long x) { | |
return sizeof(unsigned long long) * 8 - 1 - __builtin_clzll(x); // or return 63 - __builtin_clzll(x); ?? | |
} | |
template <typename T, typename Compare = std::less<T>> | |
struct ST{ | |
size_t n; // 0-indexed | |
vv<T> a; | |
// const static Compare comp; | |
template <typename ptr_t> | |
ST(ptr_t beg, ptr_t end):n(end-beg){ | |
a.resize((size_t)h_bit(n)+1); // 注意:不能写成 h_bit(n) | |
a[0].assign(beg, end); | |
rng (i, 0, SZ(a)-1) { | |
a[i+1].resize(n); | |
rng(j, 0, n - (1 << i)) { | |
a[i+1][j] = min(a[i][j], a[i][j+(1<<i)], Compare()); | |
} | |
rng(j, n-(1 << i), n) { | |
a[i+1][j] = a[i][j]; | |
} | |
} | |
} | |
T query(size_t l, size_t r) { // l <= r | |
int i = h_bit(r - l + 1); | |
return min(a[i][l], a[i][r+1-(1<<i)], Compare()); | |
} | |
}; | |
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给 ST 声明一个
static const Compare comp;
会不会跑得更快呢?