困倦奶牛排序(Sleepy Cow Sorting G) 题解

思路分析

按题目要求使用对应数据结构与算法模拟/递推求解，注意数据范围边界与时间复杂度。

参考代码

#include <iostream>
#include <vector>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    if (!(cin >> n)) return 0;
    vector<int> p(n + 1);
    for (int i = 1; i <= n; ++i) cin >> p[i];
    int k = n - 1;
    while (k >= 1 && p[k] < p[k + 1]) --k;
    cout << k << "\n";
    vector<int> bit(n + 1, 0);
    auto add = [&](int idx) {
        for (int i = idx; i <= n; i += i & -i) ++bit[i];
    };
    auto query = [&](int idx) {
        int s = 0;
        for (int i = idx; i > 0; i -= i & -i) s += bit[i];
        return s;
    };
    for (int i = k + 1; i <= n; ++i) add(p[i]);
    for (int i = 1; i <= k; ++i) {
        int steps = (k - i) + query(p[i]);
        cout << steps << (i == k ? "" : " ");
        add(p[i]);
    }
    cout << "\n";
    return 0;
}