题目链接：http://poj.org/problem?id=3264
Balanced Lineup
| Time Limit: 5000MS | Memory Limit: 65536K | |
| Total Submissions: 47515 | Accepted: 22314 | |
| Case Time Limit: 2000MS | ||
Description
For the daily milking, Farmer John's N cows (1 ≤ N ≤ 50,000) always line up in the same order. One day Farmer John decides to organize a game of Ultimate Frisbee with some of the cows. To keep things simple, he will take a contiguous range of cows from the milking lineup to play the game. However, for all the cows to have fun they should not differ too much in height.
Farmer John has made a list of Q (1 ≤ Q ≤ 200,000) potential groups of cows and their heights (1 ≤ height ≤ 1,000,000). For each group, he wants your help to determine the difference in height between the shortest and the tallest cow in the group.
Input
Line 1: Two space-separated integers, N and Q.
Lines 2..N+1: Line i+1 contains a single integer that is the height of cow i
Lines N+2..N+Q+1: Two integers A and B (1 ≤ A ≤ B ≤ N), representing the range of cows from A to B inclusive.
Lines 2..N+1: Line i+1 contains a single integer that is the height of cow i
Lines N+2..N+Q+1: Two integers A and B (1 ≤ A ≤ B ≤ N), representing the range of cows from A to B inclusive.
Output
Lines 1..Q: Each line contains a single integer that is a response to a reply and indicates the difference in height between the tallest and shortest cow in the range.
Sample Input
6 3
1
7
3
4
2
5
1 5
4 6
2 2
Sample Output
6
3
0 题目大意：给定一个数组，然后给一个区间[a,b]，输出从a到b中的最大值和最小值的差。
RMQ 和 线段树 均可
RMQ代码：
#include <stdio.h>
#define MAX(a,b) (a>b ? a:b)
#define MIN(a,b) (a>b ? b:a)
#define N 50010
int a[N],ma[N][],mi[N][]; void ST(int n)
{
int i,j;
for(i=;i<=n;i++)
mi[i][]=ma[i][]=a[i]; for (j = ; (<<j) <= n; j ++)
for (i = ; i + (<<j)- <= n; i ++)
{
ma[i][j]=MAX(ma[i][j-],ma[i+(<<(j-))][j-]);
mi[i][j]=MIN(mi[i][j-],mi[i+(<<(j-))][j-]);
}
} int rmq(int a,int b)
{
int k = ;
while((<<(k+)) <= b-a+) k++;
return MAX(ma[a][k],ma[b-(<<k)+][k])-MIN(mi[a][k],mi[b-(<<k)+][k]);
} int main()
{
int n,i,q,x,y;
while(scanf("%d %d",&n,&q)!=-)
{
for(i=;i<=n;i++)
scanf("%d",a+i);
ST(n);
for(i=;i<=q;i++)
{
scanf("%d %d",&x,&y);
printf("%d\n",rmq(x,y));
}
}
return ;
}