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63 lines
1.4 KiB
63 lines
1.4 KiB
#include <iostream>
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#include <algorithm>
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#include <cstdio>
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#include <cstring>
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using namespace std;
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const int INF = 0x3f3f3f3f;
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const int N = 50010;
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int a[N];
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struct Node {
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int l, r, mx, mi;
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} tr[N << 2];
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int mx, mi;
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void pushup(int u) {
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tr[u].mx = max(tr[u << 1].mx, tr[u << 1 | 1].mx);
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tr[u].mi = min(tr[u << 1].mi, tr[u << 1 | 1].mi);
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}
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void build(int u, int l, int r) {
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tr[u].l = l, tr[u].r = r; // POJ对于tr[u]={l,r}报编译错误，编译器版本太低，需要手动实现构造函数
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if (l == r) {
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tr[u].mx = a[l], tr[u].mi = a[l];
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return;
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}
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int mid = (l + r) >> 1;
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build(u << 1, l, mid), build(u << 1 | 1, mid + 1, r);
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pushup(u);
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}
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void query(int u, int l, int r) {
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if (l <= tr[u].l && r >= tr[u].r) {
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mx = max(mx, tr[u].mx), mi = min(mi, tr[u].mi);
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return;
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}
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int mid = (tr[u].l + tr[u].r) >> 1;
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if (l <= mid) query(u << 1, l, r);
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if (r > mid) query(u << 1 | 1, l, r);
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}
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int main() {
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#ifndef ONLINE_JUDGE
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freopen("POJ3264.in", "r", stdin);
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#endif
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// 加快读入
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ios::sync_with_stdio(false), cin.tie(0);
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int n, q;
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cin >> n >> q;
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for (int i = 1; i <= n; i++) cin >> a[i];
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build(1, 1, n);
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while (q--) {
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mx = -INF, mi = INF;
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int l, r;
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cin >> l >> r;
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query(1, l, r);
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printf("%d\n", mx - mi);
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}
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return 0;
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} |