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Cod sursa(job #343827)
#include <cstdio>
#include <cstring>
const int MAX_N = 10002;
const int INF = 0x3f3f3f3f;
int n, k, st, dr;
int a[MAX_N], s[MAX_N], dq[MAX_N];
int d[2][MAX_N], c[2][MAX_N];
inline int max(int a, int b) { return (a > b) ? a : b; }
inline int make(int l, int r)
{
return d[0][l - 1] + s[r] - s[l - 1];
}
void dinamica()
{
int i, j;
for (i = 1; i <= k; ++i)
{
d[1][0] = -INF;
st = 1, dr = 0;
for (j = 1; j <= n; ++j)
{
while (dr >= st && make(j, j) > make(dq[dr], j))
--dr;
dq[++dr] = j;
c[1][j] = make(dq[st], j);
d[1][j] = max(d[1][j - 1], c[1][j]);
}
memcpy(c[0], c[1], sizeof(c[0]));
memcpy(d[0], d[1], sizeof(d[0]));
}
}
int main()
{
int i;
freopen("ferma.in", "r", stdin);
freopen("ferma.out", "w", stdout);
scanf("%d %d", &n, &k);
for (i = 1; i <= n; s[i] = s[i - 1] + a[i], ++i)
scanf("%d", &a[i]);
dinamica();
int sol = d[0][n];
for (i = 1; i <= n; ++i)
{
c[0][i] = s[i];
d[0][i] = max(d[0][i - 1], s[i]);
}
dinamica();
for (i = 1; i <= n; ++i)
sol = max(sol, c[0][i] + s[n] - s[i]);
printf("%d\n", (sol < 0) ? 0 : sol);
}