#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
template <class T>
void read(T &x)
{
x = 0;
register int c;
while ((c = getchar()) && (c > '9' || c < '0'))
;
for (; c >= '0' && c <= '9'; c = getchar())
x = x * 10 + c - '0';
}
constexpr bool typetest = 0;
constexpr int N = 3e5 + 5;
constexpr ll Inf = 1e17;
#define Sum(x, y) ((x == -Inf || y == -Inf) ? -Inf : (x + y))
struct node
{
ll ans, pre, suf, sum;
int l, r, rpre, lsuf;
node(ll v = -Inf, int x = 0, int y = 0)
{
ans = pre = suf = sum = v;
l = x;
r = y;
rpre = y;
lsuf = x;
}
friend node Combine(const node &a, const node &b)
{
node ans(-Inf, 0, 0);
ans.sum = Sum(a.sum, b.sum);
ans.pre = a.pre;
ans.rpre = a.rpre;
ans.suf = b.suf;
ans.lsuf = b.lsuf;
if (a.ans > b.ans)
{
ans.ans = a.ans;
ans.l = a.l;
ans.r = a.r;
}
else
{
ans.ans = b.ans;
ans.l = b.l;
ans.r = b.r;
}
if (ans.ans < Sum(a.suf, b.pre))
{
ans.ans = Sum(a.suf, b.pre);
ans.l = a.lsuf;
ans.r = b.rpre;
}
if (ans.pre < Sum(a.sum, b.pre))
{
ans.pre = Sum(a.sum, b.pre);
ans.rpre = b.rpre;
}
if (ans.suf < Sum(a.suf, b.sum))
{
ans.suf = Sum(a.suf, b.sum);
ans.lsuf = a.lsuf;
}
return ans;
}
};
struct SegmentTree
{
vector<node> st, rv;
vector<bool> lazy;
int n;
SegmentTree()
{
}
void Assign(int n)
{
this->n = n;
st.resize(n * 4 + 2);
rv.resize(n * 4 + 2);
lazy.assign(n * 4 + 2, 0);
}
void Build(int id, int l, int r, ll a[N])
{
if (l == r)
{
st[id] = node(a[l], l, l);
rv[id] = node(-a[l], l, l);
return;
}
Build(id << 1, l, (l + r) / 2, a);
Build(id << 1 | 1, (l + r) / 2 + 1, r, a);
st[id] = Combine(st[id << 1], st[id << 1 | 1]);
rv[id] = Combine(rv[id << 1], rv[id << 1 | 1]);
}
void Build(ll a[N])
{
Build(1, 1, n, a);
}
void Push(int id)
{
if (lazy[id])
{
swap(st[id << 1], rv[id << 1]);
lazy[id << 1] = !lazy[id << 1];
swap(st[id << 1 | 1], rv[id << 1 | 1]);
lazy[id << 1 | 1] = !lazy[id << 1 | 1];
lazy[id] = 0;
}
}
void Update(int id, int l, int r, const int &a, const int &b)
{
if (l > b || r < a)
return;
if (l >= a && r <= b)
{
swap(rv[id], st[id]);
lazy[id] = !lazy[id];
return;
}
Push(id);
Update(id << 1, l, (l + r) / 2, a, b);
Update(id << 1 | 1, (l + r) / 2 + 1, r, a, b);
st[id] = Combine(st[id << 1], st[id << 1 | 1]);
rv[id] = Combine(rv[id << 1], rv[id << 1 | 1]);
}
void Update(int l, int r)
{
Update(1, 1, n, l, r);
}
} f;
int n, k;
ll a[N];
void Read()
{
freopen("test.INP", "r", stdin);
freopen("test.OUT", "w", stdout);
cin >> n >> k;
for (int i = 1; i <= n; ++i)
cin >> a[i];
}
void Solve()
{
f.Assign(n);
f.Build(a);
ll ans(0);
while (k--)
{
if (f.st[1].ans < 0)
break;
ans += f.st[1].ans;
f.Update(f.st[1].l, f.st[1].r);
}
cout << ans;
}
int32_t main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t(1);
if (typetest)
cin >> t;
for (int _ = 1; _ <= t; ++_)
{
//cout << "Case #" << _ << ": ";
Read();
Solve();
}
//cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
}
Compilation message
feast.cpp: In function 'void read(T&)':
feast.cpp:12:18: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
12 | register int c;
| ^
feast.cpp: In function 'void Read()':
feast.cpp:163:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
163 | freopen("test.INP", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
feast.cpp:164:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
164 | freopen("test.OUT", "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
113 ms |
262148 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
111 ms |
262148 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
122 ms |
262148 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
118 ms |
262148 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
118 ms |
262148 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
118 ms |
262148 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
113 ms |
262148 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |