题目：Balanced lineup

题目说的很清楚了，没有修改，直接RMQ，模板题。

代码：

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <cmath>
const int N = 5e4 + 5;
using namespace std;
int n, m, a[N], f1[N][20], f2[N][20];
int main()
{
    scanf("%d %d", &n, &m);
    for(int i = 1; i <= n; i++)
        scanf("%d", &a[i]), f1[i][0] = f2[i][0] = a[i];
    for(int j = 1; (1<<j) <= n; j++)
        for(int i = 1; i + (1<<j) - 1 <= n; i++)
        {
            f1[i][j] = max(f1[i][j-1], f1[i + (1<< (j-1))][j-1]);
            f2[i][j] = min(f2[i][j-1], f2[i + (1<< (j-1))][j-1]);
        }
    while(m--)
    {
        int l, r;
        scanf("%d %d", &l, &r);
        int j=log2(r - l + 1);
        printf("%d\n", max(f1[l][j], f1[r - (1<<j) + 1][j]) - min(f2[l][j], f2[r - (1<<j) + 1][j]));
    }
    return 0;
}