#line 1 "test/aoj_3111.test.cpp"
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=3111"
#include <cstdint>
#include <cstdio>
#include <algorithm>
#include <vector>
#line 1 "utility/literals.cpp"
/**
* @brief ユーザ定義リテラル
* @author えびちゃん
*/
#include <cstddef>
#line 11 "utility/literals.cpp"
constexpr intmax_t operator ""_jd(unsigned long long n) { return n; }
constexpr uintmax_t operator ""_ju(unsigned long long n) { return n; }
constexpr size_t operator ""_zu(unsigned long long n) { return n; }
constexpr ptrdiff_t operator ""_td(unsigned long long n) { return n; }
constexpr int8_t operator ""_i8(unsigned long long n) { return n; }
constexpr int16_t operator ""_i16(unsigned long long n) { return n; }
constexpr int32_t operator ""_i32(unsigned long long n) { return n; }
constexpr int64_t operator ""_i64(unsigned long long n) { return n; }
constexpr uint8_t operator ""_u8(unsigned long long n) { return n; }
constexpr uint16_t operator ""_u16(unsigned long long n) { return n; }
constexpr uint32_t operator ""_u32(unsigned long long n) { return n; }
constexpr uint64_t operator ""_u64(unsigned long long n) { return n; }
#line 1 "utility/monoid/max_subsum.cpp"
/**
* @brief 部分和の最大値を得る演算のモノイドクラス
* @author えびちゃん
*/
#line 11 "utility/monoid/max_subsum.cpp"
template <typename Tp>
class max_subsum_monoid {
public:
using size_type = size_t;
using value_type = Tp;
private:
value_type M_pre = 0, M_suf = 0, M_sub = 0, M_whole = 0;
size_type M_length = 0;
public:
max_subsum_monoid() = default; // identity
max_subsum_monoid(value_type const& x):
M_pre(x), M_suf(x), M_sub(x), M_whole(x), M_length(1) {}
max_subsum_monoid(value_type const& x, value_type n):
M_pre(x*n), M_suf(x*n), M_sub(x*n), M_whole(x*n), M_length(n)
{
if (x < 0) M_pre = M_suf = M_sub = x;
}
max_subsum_monoid& operator +=(max_subsum_monoid const& that) {
if (that.M_length == 0) return *this;
if (M_length == 0) return (*this = that);
M_sub = std::max({M_sub, M_suf + that.M_pre, that.M_sub});
M_suf = std::max(M_suf + that.M_whole, that.M_suf);
M_pre = std::max(M_pre, M_whole + that.M_pre);
M_whole += that.M_whole;
M_length += that.M_length;
return *this;
}
friend bool operator ==(max_subsum_monoid const& lhs, max_subsum_monoid const& rhs) {
if (lhs.M_length == 0 && rhs.M_length == 0) return true;
return (
lhs.M_length == rhs.M_length
&& lhs.M_pre == rhs.M_pre
&& lhs.M_suf == rhs.M_suf
&& lhs.M_sub == rhs.M_sub
&& lhs.M_whole == rhs.M_whole
);
}
friend max_subsum_monoid operator +(max_subsum_monoid lhs, max_subsum_monoid const& rhs) {
return lhs += rhs;
}
friend bool operator !=(max_subsum_monoid const& lhs, max_subsum_monoid const& rhs) {
return !(lhs == rhs);
}
size_type length() const noexcept { return M_length; }
value_type const& get() const { return M_sub; }
};
#line 1 "DataStructure/basic_segment_tree.cpp"
/**
* @brief 単一更新セグメント木
* @author えびちゃん
* @docs docs/basic_segment_tree.md
*/
#line 13 "DataStructure/basic_segment_tree.cpp"
template <typename Monoid>
class basic_segment_tree {
public:
using value_type = Monoid;
using size_type = size_t;
private:
std::vector<value_type> M_c;
size_type M_n;
public:
basic_segment_tree() = default;
explicit basic_segment_tree(size_type n): M_c(n+n), M_n(n) {}
explicit basic_segment_tree(size_type n, value_type const& x):
M_c(n+n, x), M_n(n)
{
for (size_type i = n; i--;) M_c[i] = M_c[i<<1|0] + M_c[i<<1|1];
}
template <typename InputIt>
basic_segment_tree(InputIt first, InputIt last) {
std::vector<value_type> tmp(first, last);
M_n = tmp.size();
M_c.resize(M_n);
M_c.insert(M_c.end(), tmp.begin(), tmp.end());
for (size_type i = M_n; i--;) M_c[i] = M_c[i<<1|0] + M_c[i<<1|1];
}
void assign(size_type n, value_type const& x) {
M_c.assign(n+n, x);
M_n = n;
for (size_type i = n; i--;) M_c[i] = M_c[i<<1|0] + M_c[i<<1|1];
}
template <typename InputIt>
void assign(InputIt first, InputIt last) {
std::vector<value_type> tmp(first, last);
M_n = tmp.size();
M_c.resize(M_n);
M_c.insert(M_c.end(), tmp.begin(), tmp.end());
for (size_type i = M_n; i--;) M_c[i] = M_c[i<<1|0] + M_c[i<<1|1];
}
void set(size_type i, value_type const& x) {
i += M_n;
M_c[i] = x;
while (i > 1) {
i >>= 1;
M_c[i] = M_c[i<<1|0] + M_c[i<<1|1];
}
}
void set(size_type i, value_type&& x) {
i += M_n;
M_c[i] = std::move(x);
while (i > 1) {
i >>= 1;
M_c[i] = M_c[i<<1|0] + M_c[i<<1|1];
}
}
value_type const& operator [](size_type i) const { return M_c[i + M_n]; }
value_type fold(size_type l, size_type r) const {
value_type resl{}, resr{};
l += M_n;
r += M_n;
while (l < r) {
if (l & 1) resl += M_c[l++];
if (r & 1) resr = M_c[--r] + std::move(resr);
l >>= 1;
r >>= 1;
}
return resl += resr;
}
template <typename Predicate>
size_type foldl_bisect(size_type l, Predicate pred) const {
size_type r = M_n+M_n;
value_type x{};
size_type h = 0;
if (l == M_n) return pred(x)? -1: l;
l += M_n;
auto bisect = [&](size_type v) -> size_type {
while (v < M_n) {
v <<= 1;
if (pred(x + M_c[v])) x += M_c[v++];
}
return v - M_n;
};
for (; l < r; ++h, l >>= 1, r >>= 1) {
if (l & 1) {
if (!pred(x + M_c[l])) return bisect(l);
x += M_c[l];
++l;
}
if (r & 1) --r;
}
while (r <<= 1, h--) {
if (((r+1) << h) <= M_n+M_n) {
if (!pred(x + M_c[r])) return bisect(r);
x += M_c[r];
++r;
}
}
return -1;
}
template <typename Predicate>
size_type foldr_bisect(size_type r, Predicate pred) const {
size_type l = M_n;
value_type x{};
size_type h = 0;
if (r == 0) return pred(x)? -1: 0;
r += M_n;
auto bisect = [&](size_type v) -> size_type {
while (v < M_n) {
v = (v << 1 | 1);
if (pred(M_c[v] + x)) x = M_c[v--] + std::move(x);
}
return v - M_n;
};
for (; l < r; ++h, l >>= 1, r >>= 1) {
if (l & 1) ++l;
if (r & 1) {
--r;
if (!pred(M_c[r] + x)) return bisect(r);
x = M_c[r] + std::move(x);
}
}
while (l <<= 1, h--) {
if (((l-1) << h) >= M_n) {
--l;
if (!pred(M_c[l] + x)) return bisect(l);
x = M_c[l] + std::move(x);
}
}
return -1;
}
};
#line 11 "test/aoj_3111.test.cpp"
int main() {
size_t n, q;
scanf("%zu %zu", &n, &q);
std::vector<intmax_t> a(n);
for (auto& ai: a) scanf("%jd", &ai);
basic_segment_tree<max_subsum_monoid<intmax_t>> st(a.begin(), a.end());
printf("%jd\n", std::max(st.fold(0, n).get(), 0_jd));
for (size_t i = 0; i < q; ++i) {
size_t k;
intmax_t x;
scanf("%zu %jd", &k, &x);
--k;
st.set(k, x);
printf("%jd\n", std::max(st.fold(0, n).get(), 0_jd));
}
}