RMQ模板

void RMQ_init()
{
    for(int i=1; i<=n; i++) dp[i][0]=s[i];
    for(int j=1; (1<<j)<=n; j++)
        for(int i=1;i+(1<<j)-1<=n;i++)
            dp[i][j]=max(dp[i][j-1],dp[i+(1<<(j-1))][j-1]);
}
int RMQ(int L,int R)
{
    int k=0;
    while((1<<(k+1))<=R-L+1) k++;
    return max(dp[L][k],dp[R-(1<<k)+1][k]);
}

　　

附带讲解:

http://blog.csdn.net/liang5630/article/details/7917702

#include <cstring>
#include <cmath>
#include <cstdio>
#include <algorithm>
#define N 50010
using namespace std;

int maxArr[N][16], minArr[N][16];
int n, q, num[N];

void Sparse_Table(){
	int l = (int)(log((double)n) / log(2.0));
	for (int j = 1;j <= l;j++)
		for (int i = 1; i + (1 << (j - 1) ) - 1 <= n;++i){
			maxArr[i][j] = max(maxArr[i][j - 1], maxArr[i + (1 << (j - 1))][j - 1]);
			minArr[i][j] = min(minArr[i][j - 1], minArr[i + (1 << (j - 1))][j - 1]);
		}
}

int rmq(int l, int r){
	int k = (int)(log((double)(r - l + 1)) / log(2.0));
	int Max = max(maxArr[l][k], maxArr[r - (1 << k) + 1][k]);
	int Min = min(minArr[l][k], minArr[r - (1 << k) + 1][k]);
	return Max - Min;
}

int main(){
	while (~scanf("%d %d", &n, &q)){
		memset(maxArr, 0, sizeof(maxArr));
		memset(minArr, 0, sizeof(minArr));
		for (int i = 1;i <= n;i++){
			scanf("%d", &num[i]);
			maxArr[i][0] = minArr[i][0] = num[i];
		}
		Sparse_Table();
		int l, r;
		while (q--){
			scanf("%d%d", &l, &r);
			printf("%d
", rmq(l, r));
		}
	}
	return 0;
}