#include<iostream>
#include<algorithm>
using namespace std;
int MaxNum[500][50000];
int MinNum[500][50000];
int a[50000];
void ST(int N) {
int temp = (int)(log((double)N) / log(2.0));
for (int i = 0; i < N; i++) MaxNum[0][i] = a[i],MinNum[0][i]=a[i];
for (int i = 1; i <= temp; ++i)
for (int j = 0; j + (1 << i)-2 <N; ++j)
MaxNum[i][j] = max(MaxNum[i - 1][j], MaxNum[i - 1][j + (1 << (i - 1))]),
MinNum[i][j] = min(MinNum[i - 1][j], MinNum[i - 1][j + (1 << (i - 1))]) ;
}
int query(int L, int R)
{
int k = (int)(log((double)(R - L + 1)) / log(2.0));
return max(MaxNum[k][L], MaxNum[k][R - (1 << k) + 1])-min(MinNum[k][L], MinNum[k][R - (1 << k) + 1]);
}
int main()
{
int n,m; cin >> n>>m;
for (int i = 0; i < n; ++i)cin >> a[i];
ST(n);
while (m--)
{
int i, j; cin >> i >> j;
cout << query(i - 1, j - 1)<<endl;
}
}
RMQ-区间最大差值(ST表)
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转载自blog.csdn.net/qq_31741481/article/details/84347098
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