rmq

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#include <cstdio>  
#include <cstring>  
#include <cmath>  
#include <iostream>  
using namespace std;  
const int MAXN = 100117;  
int n,query;  
int num[MAXN];  
  
int F_Min[MAXN][20],F_Max[MAXN][20];  
  
void Init()  
{  
    for(int i = 1; i <= n; i++)  
    {  
        F_Min[i][0] = F_Max[i][0] = num[i];  
    }  
  
    for(int i = 1; (1<<i) <= n; i++)  //按区间长度递增顺序递推  
    {  
        for(int j = 1; j+(1<<i)-1 <= n; j++)  //区间起点  
        {  
            F_Max[j][i] = max(F_Max[j][i-1],F_Max[j+(1<<(i-1))][i-1]);  
            F_Min[j][i] = min(F_Min[j][i-1],F_Min[j+(1<<(i-1))][i-1]);  
        }  
    }  
}  
  
int Query_max(int l,int r)  
{  
    int k = (int)(log(double(r-l+1))/log((double)2));  
    return max(F_Max[l][k], F_Max[r-(1<<k)+1][k]);  
}  
  
int Query_min(int l,int r)  
{  
    int k = (int)(log(double(r-l+1))/log((double)2));  
    return min(F_Min[l][k], F_Min[r-(1<<k)+1][k]);  
}  
  
int main()  
{  
    int a,b;  
    scanf("%d %d",&n,&query);  
    for(int i = 1; i <= n; i++)  
        scanf("%d",&num[i]);  
    Init();  
    while(query--)  
    {  
        scanf("%d %d",&a,&b);  
        printf("区间%d到%d的最大值为：%d
",a,b,Query_max(a,b));  
        printf("区间%d到%d的最小值为：%d
",a,b,Query_min(a,b));  
        printf("区间%d到%d的最大值和最小值只差为：%d
",a,b,Query_max(a,b)-Query_min(a,b));  
    }  
    return 0;  
}  

http://blog.csdn.net/u012860063/article/details/40752197