51nod 1174 区间中最大的数(RMQ)

题目链接：http://www.51nod.com/onlineJudge/questionCode.html#!problemId=1174

RMQ的入门模板题...

AC代码：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#define maxn 10005
using namespace std;
int n,m;
int pre[maxn][25];

void ST(){
  for(int j = 1; (1<<j) <= n; j++){
    for(int i = 1; (i + (1<<j) - 1) <= n; i++){
      pre[i][j] = max(pre[i][j-1], pre[i + (1 << (j-1) )][j-1]);
    }
  }
}

void RMQ(int l,int r){
  int k = (int)(log(r-l+1.0)/log(2.0));
  int ans = max(pre[l][k],pre[r - (1<<k) + 1][k]);
  printf("%d\n",ans);
}

int main()
{
  scanf("%d",&n);
  for(int i=1;i<=n;i++){
    scanf("%d",&pre[i][0]);
  }
  ST();
  scanf("%d",&m);
  while(m--){
    int x,y;
    scanf("%d%d",&x,&y);
    x++;y++;
    RMQ(x,y);
  }
  return 0;
}