RMQ o(nlogn) o(1)

标签：acm

#include <iostream>
#include <cmath>
#include <cstdio>

using namespace std;
#define maxn 100000

int a[maxn];
int n;
int d[maxn][20];

void RMQ_init()
{
    for(int i=1; i<=n; i++)
        d[i][0] = a[i];

    for(int j=1; (1<<j)<=n; j++)
        for(int i=1; i+j-1<=n; i++)
        {
            d[i][j] = min(d[i][j-1], d[i+(1<<(j-1))][j-1]);
        }
}

int RMQ(int L, int R)
{
    int k = (int)(log((double)R-L+1)/log(2.0));
    return min(d[L][k], d[R-(1<<k)+1][k]);
}

int main()
{
    cin>>n;
    for(int i=1; i<=n; i++)
        cin>>a[i];
    RMQ_init();
    int q;
    cin>>q;
    int l, r;
    while(q--)
    {
        cin>>l>>r;
        cout<<RMQ(l, r)<<endl;
    }
    return 0;
}

/*

10
1 6 5 4 8 7 5 4 3 3
100
*/

RMQ o(nlogn) o(1)

标签：acm

原文地址：http://blog.csdn.net/dojintian/article/details/46484019