Frequent values
Description
You are given a sequence of n integers a1 , a2 , ... , an in non-decreasing order. In addition to that, you are given several queries consisting of indices i and j (1 ≤ i ≤ j ≤ n). For each query, determine the most frequent value among the integers ai , ... , aj.
Input
The input consists of several test cases. Each test case starts with a line containing two integers n and q (1 ≤ n, q ≤ 100000). The next line contains n integers a1 , ... , an (-100000 ≤ ai ≤ 100000, for each i ∈ {1, ..., n}) separated by spaces. You can assume that for each i ∈ {1, ..., n-1}: ai ≤ ai+1. The following q lines contain one query each, consisting of two integers i and j (1 ≤ i ≤ j ≤ n), which indicate the boundary indices for the
query.
The last test case is followed by a line containing a single 0.
Output
For each query, print one line with one integer: The number of occurrences of the most frequent value within the given range.
Sample Input
10 3
-1 -1 1 1 1 1 3 10 10 10
2 3
1 10
5 10
0
Sample Output
1
4
3
题意：查找区间内数出现最多的次数
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define maxn 100010
#define Max(a, b) a > b ? a : b
int num[maxn], v[maxn], rq[maxn][20];
void build(int n)
{
int i, j, m, r = n, c = log((double)n) / log(2.0);
for (i = 1; i <= n; i++)
{
rq[i][0] = v[i];
}
for (i = 1; i <= c; i++)
{
for (j = 1; j <= r; j++)
{
m = j + (1 << (i - 1));a
if (m <= r)
{
rq[j][i] = Max(rq[j][i-1], rq[m][i-1]);
}
else
{
rq[j][i] = rq[j][i-1];
}
}
}
}
int rmq(int l, int r)
{
int len = r - l + 1;
int k = log(double(len)) / log(2.0);
int m = r - (1 << k) + 1;
return Max(rq[l][k], rq[m][k]);
}
int query(int l, int r)
{
int left, i;
if (num[l] == num[r])
{
return r - l + 1;
}
for (i = l; ; i++)
{
if (v[i] == 1)
{
left = i - l;
break;
}
}
return Max(left, rmq(i, r));
}
int main()
{
int n, m, i, l, r;
while (scanf("%d%d", &n, &m) == 2)
{
scanf("%d", &num[1]);
v[1] = 1;
for (i = 2; i <= n; i++)
{
scanf("%d", &num[i]);
if (num[i] == num[i-1])
{
v[i] = v[i-1] + 1;
}
else
{
v[i] = 1;
}
}
build(n);
while (m--)
{
scanf("%d%d", &l, &r);
printf("%d\n", query(l, r));
}
}
return 0;
}