46 lines
1.2 KiB
C++
46 lines
1.2 KiB
C++
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#include <cstring>
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#include <iostream>
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#include <vector>
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#include <algorithm>
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using namespace std;
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const int INF = 0x3f3f3f3f;
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/*
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其实跟 普通平衡树 使用vector方法差不多，只是要注意先插入一个-INF和INF的数用来防止使用lower_bound和upper_bound的时候越界。
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*/
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// 727 ms
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vector<int> a;
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int main() {
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int n;
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cin >> n;
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a.push_back(-INF), a.push_back(INF);
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//首次插入
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int x;
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int res = 0;
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//后续插入
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for (int i = 1; i <= n; i++) {
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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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int prev = lower_bound(a.begin(), a.end(), x) - a.begin();
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if (a[prev] != x) prev = lower_bound(a.begin(), a.end(), x) - a.begin() - 1;
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//如果序列之中没有等于当前的数，那我们取严格小于当前的数
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int next = upper_bound(a.begin(), a.end(), x) - a.begin(); //后继
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//按题目要求来计算
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res += min(abs(x - a[prev]), abs(a[next] - x));
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}
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//将x放入vector中
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a.insert(lower_bound(a.begin(), a.end(), x), x);
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}
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//输出
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printf("%d\n", res);
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return 0;
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}
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