108 lines
2.7 KiB
C++
108 lines
2.7 KiB
C++
#include <iostream>
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#include <algorithm>
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#include <cstring>
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#include <cstdio>
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#include <unordered_map>
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#include <vector>
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using namespace std;
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typedef long long LL;
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const int N = 30010, M = 100010;
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typedef pair<int, int> PII;
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// 线段树结构体
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struct Node {
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int l, r;
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LL sum; // 区间和
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} tr[N << 2];
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int n, m; // n个数字的原始数列，m次询问
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int a[N]; // 原始数组
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LL ans[M]; // 问题答案
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void pushup(int u) {
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tr[u].sum = tr[u << 1].sum + tr[u << 1 | 1].sum;
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}
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void build(int u, int l, int r) {
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tr[u] = {l, r};
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int mid = (l + r) >> 1;
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if (l == r) return;
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build(u << 1, l, mid), build(u << 1 | 1, mid + 1, r);
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pushup(u); // 套路，其实本题不需要pushup
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}
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void modify(int u, int x, int v) {
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if (tr[u].l == tr[u].r) {
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tr[u].sum += v;
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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 (x <= mid) modify(u << 1, x, v);
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if (x > mid) modify(u << 1 | 1, x, v);
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pushup(u);
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}
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LL query(int u, int l, int r) {
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if (l <= tr[u].l && tr[u].r <= r) return tr[u].sum;
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LL ans = 0;
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int mid = (tr[u].l + tr[u].r) >> 1;
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if (l <= mid) ans += query(u << 1, l, r);
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if (r >= mid + 1) ans += query(u << 1 | 1, l, r);
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return ans;
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}
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/*
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参考答案:
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1
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5
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6
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3
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6
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*/
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int main() {
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#ifndef ONLINE_JUDGE
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freopen("HDU3333.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 T;
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cin >> T;
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while (T--) {
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// 本题关键词：区间离线查询
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unordered_map<int, int> b;
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vector<PII> q;
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memset(ans, 0, sizeof ans);
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memset(tr, 0, sizeof tr);
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cin >> n;
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// 构建线段树
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build(1, 1, n);
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for (int i = 1; i <= n; i++) cin >> a[i];
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cin >> m;
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// ① 记录离线查询，三个要素：序号，左端点，右端点
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for (int i = 1; i <= m; i++) {
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int l, r;
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cin >> l >> r;
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q[i] = {l, r};
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}
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// 通过单点修改，修改线段树的统计信息
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for (int i = 1; i <= n; i++) {
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// 根据值，利用HASH表，找出此值原来的位置
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// 如果有相同值出现，则旧位置上减去a[i],然后更新HASH，在新位置上+a[i]
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if (b.count(a[i])) modify(1, b[a[i]], -a[i]);
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b[a[i]] = i;
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modify(1, i, a[i]);
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}
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for (int i = 1; i <= m; i++)
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ans[i] = query(1, q[i].first, q[i].second);
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// 输出m次询问的结果
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for (int i = 1; i <= m; i++) printf("%lld\n", ans[i]);
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}
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return 0;
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} |