112 lines
2.4 KiB
C++
112 lines
2.4 KiB
C++
#include <cstdio>
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#include <cstring>
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#include <algorithm>
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#include <iostream>
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using namespace std;
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typedef long long LL;
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const int N = 33010;
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const int INF = 0x3f3f3f3f;
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// AC 213 ms
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int n;
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struct Node {
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int l, r;
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int key, val;
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int cnt;
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int size;
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} tr[N];
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int root, idx;
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void pushup(int p) {
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tr[p].size = tr[tr[p].l].size + tr[tr[p].r].size + tr[p].cnt;
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}
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int get_node(int key) {
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tr[++idx].key = key;
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tr[idx].val = rand();
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tr[idx].cnt = tr[idx].size = 1;
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return idx;
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}
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void zig(int &p) {
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int q = tr[p].l;
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tr[p].l = tr[q].r;
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tr[q].r = p;
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p = q;
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pushup(tr[p].r);
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pushup(p);
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}
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void zag(int &p) {
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int q = tr[p].r;
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tr[p].r = tr[q].l;
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tr[q].l = p;
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p = q;
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pushup(tr[p].l);
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pushup(p);
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}
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void build() {
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get_node(-INF), get_node(INF);
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root = 1, tr[1].r = 2;
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pushup(root);
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if (tr[1].val < tr[2].val) zag(root);
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}
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void insert(int &p, int key) {
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if (!p)
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p = get_node(key);
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else {
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if (tr[p].key == key)
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tr[p].cnt++;
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else {
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if (tr[p].key > key) {
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insert(tr[p].l, key);
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if (tr[tr[p].l].val > tr[p].val) zig(p);
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} else {
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insert(tr[p].r, key);
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if (tr[tr[p].r].val > tr[p].val) zag(p);
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}
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}
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}
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pushup(p);
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}
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// 注意这里与AcWing 253在细节上的区别，那个是严格小于key的最大数
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// 找到小于等于key的最大数
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int get_prev(int p, int key) {
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if (!p) return -INF;
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if (tr[p].key > key) return get_prev(tr[p].l, key);
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return max(tr[p].key, get_prev(tr[p].r, key));
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}
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// 注意这里与AcWing 253在细节上的区别，那个是严格大于key的最小数
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// 找到大于等于key的最小数
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int get_next(int p, int key) {
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if (!p) return INF;
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if (tr[p].key < key) return get_next(tr[p].r, key);
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return min(tr[p].key, get_next(tr[p].l, key));
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}
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int main() {
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//加快读入
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ios::sync_with_stdio(false), cin.tie(0);
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//构建Treap
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build();
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cin >> n;
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LL res = 0;
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for (int i = 1; i <= n; i++) {
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int x;
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cin >> x;
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if (i == 1)
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res += x;
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else
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res += min(x - get_prev(root, x), get_next(root, x) - x);
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//加入
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insert(root, x);
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}
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//结果
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printf("%lld\n", res);
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return 0;
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} |