题目大意:
题解:
ST表模板。
#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
int num[50005], minn[50005][50], maxn[50005][50], n, q;
void stPreWork() {
for (int i = 1; i <= n; ++i) {
minn[i][0] = num[i];
maxn[i][0] = num[i];
}
for (int j = 1; (1 << j) <= n; ++j) {
for (int i = 1; i + (1 << j) - 1 <= n; ++i) {
minn[i][j] = min(minn[i][j - 1], minn[i + (1 << (j - 1))][j - 1]);
maxn[i][j] = max(maxn[i][j - 1], maxn[i + (1 << (j - 1))][j - 1]);
}
}
}
int stQuery(int l, int r) {
int k = 0;
while (l + (1 << (k + 1)) - 1 <= r) {
k++;
}
return max(maxn[l][k], maxn[r - (1 << k) + 1][k]) - min(minn[l][k], minn[r - (1 << k) + 1][k]);
}
int main() {
scanf("%d%d", &n, &q);
for (int i = 1; i <= n; ++i) {
scanf("%d", &num[i]);
}
stPreWork();
for (int i = 1, l, r; i <= q; ++i) {
scanf("%d%d", &l, &r);
printf("%d\n", stQuery(l, r));
}
return 0;
}