POJ 3368
题目大意
暂无
题目解法
暂无
RTFC
#include <cctype>
#include <cstdio>
#include <cstring>
inline void read(int &x)
{
int ch = x = 0, flag = 1;
while (!isdigit(ch = getchar()))
if (ch == '-') flag = -1;
for (; isdigit(ch); ch = getchar()) x = x * 10 + ch - '0';
x *= flag;
}
inline int max(int x, int y) { return x > y ? x : y; }
int L[100010], R[100010], C[100010], P[100010], F[100010][18], Log[100010];
int main()
{
Log[0] = -1;
for (int i = 1; i < 100010; i++) Log[i] = Log[i >> 1] + 1;
int n, q;
while (read(n), n)
{
memset(C, 0, sizeof(C));
read(q);
int bcnt = 0;
for (int i = 1, prev = -0x3f3f3f3f, now; i <= n; i++)
{
read(now);
if (now != prev)
bcnt++, L[bcnt] = i, R[bcnt - 1] = i - 1;
C[bcnt]++;
P[i] = bcnt;
prev = now;
}
R[bcnt] = n;
for (int i = 1; i <= bcnt; i++) F[i][0] = C[i];
for (int j = 1; (1 << j) <= bcnt; j++)
for (int i = 1; i <= bcnt; i++)
F[i][j] = max(F[i][j - 1], F[i + (1 << (j - 1))][j - 1]);
while (q--)
{
int x, y;
read(x), read(y);
if (P[y] > P[x])
{
int ans = max(R[P[x]] - x + 1, y - L[P[y]] + 1);
int bx = P[x] + 1, by = P[y] - 1;
if (by >= bx)
{
int k = Log[by - bx + 1];
ans = max(ans, max(F[bx][k], F[by - (1 << k) + 1][k]));
}
printf("%d\n", ans);
}
else
printf("%d\n", y - x + 1);
}
}
return 0;
}