RMQ POJ3264

RMQ

RMQ(Regional Maximize/Minmize Query)区间最值问题

一般的处理方法是ST表,即对于序列A的每个位置i处理出一个数组dp[i][j] 表示 [i……i+(2^j)-1]这个区间的最值(也就是i往后走2^j步)(倍增思想)

最小区间[i,i],显然dp[i][0] = a[i];

继续往上推,dp[i][j]可以拆分为两个更小的部分dp[i][j-1]dp[i+(2^(j-1))][j-1]……

 

RMQ

void RMQ()
{
    for(int j=1;j<=30;++j){
        for(int i=1;i<=n;++i){
            if(i+(1<

 

最大最小值询问

一段区间可以被两段2^k长度覆盖(可能有重合),所以就可以轻松地询问最大最小值辣

int qmax(int l,int r)
{
    int k=(int)(log(r-l+1.0)/log(2.0));
    return max(ma[l][k],ma[r-(1<

 

POJ3264

Balanced Lineup

Time Limit: 5000MS   Memory Limit: 65536K
Total Submissions: 64360   Accepted: 30000
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.

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

 

直接上代码辣

#include 
#include 
#include 
using namespace std;

const int maxn=50020;

int n,q;
int ma[maxn<<1][30];
int mi[maxn<<1][30];

void RMQ()
{
    for(int j=1;j<=30;++j){
        for(int i=1;i<=n;++i){
            if(i+(1<

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