USACO 1月 2021-2022 January Contest Silver银组 题解

你好啊我又又又来了
要准备usaco的铁铁们可以参考这个文章哦！

想刷好USACO——看这篇文章就够了_GeekAlice的博客-优快云博客我最近是发现了一个很好用的网站https://blog.youkuaiyun.com/GeekAlice/article/details/122291933?spm=1001.2014.3001.5501
这次是银组的题解，

如果你想看铜组的话，传送门在这里：

USACO 1月 2021-2022 Contest Bronze 题解_GeekAlice的博客-优快云博客USACO 2021-22 January Contest Bronze 完整版题解https://blog.youkuaiyun.com/GeekAlice/article/details/122798286?spm=1001.2014.3001.5502

:))

话不多说，上题解：

✓
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题解：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
 
public class SearchingForSoulmates {
 
    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder out = new StringBuilder();
        for (int t = Integer.parseInt(in.readLine()); t > 0; t--) {
            StringTokenizer tokenizer = new StringTokenizer(in.readLine());
            long cow1 = Long.parseLong(tokenizer.nextToken());
            long cow2 = Long.parseLong(tokenizer.nextToken());
            long answer = Long.MAX_VALUE;
            for (int removed = 0; cow2 >> removed > 0; removed++) {
                long here = 0;
                long prefix = cow2 >> removed;
                long cow = cow1;
                while (cow > prefix) {
                    if (cow % 2L == 1L) {
                        cow++;
                        here++;
                    }
                    cow /= 2L;
                    here++;
                }
                here += prefix - cow;
                here += removed;
                here += Long.bitCount(cow2 & ((1L << removed) - 1L));
                answer = Math.min(answer, here);
            }
            out.append(answer).append('\n');
        }
        System.out.print(out);
    }
}

 

#include <bits/stdc++.h>
using namespace std;
int64_t ans = 0;
int N; 
void add_contribution(const vector<int>& h) {
	vector<int> with_h(N+1);
	for (int i = 0; i < N; ++i) with_h[h[i]] = i;
	set<int> present;
	for (int cur_h = N; cur_h; --cur_h) {
		auto it = present.insert(with_h[cur_h]).first;
		if (next(it) != end(present)) ans += *next(it)-*it+1;
	}  
}
void add_contribution_ll(const vector<int>& h) {
	vector<int> with_h(N+1);
	for (int i = 0; i < N; ++i) with_h[h[i]] = i;
	vector<int> pre(N), nex(N);
	for (int i = 0; i < N; ++i) {
		pre[i] = i-1;
		nex[i] = i+1;
	}
	for (int cur_h = 1; cur_h <= N; ++cur_h) {
		int pos = with_h[cur_h];
		int p = pre[pos], n = nex[pos];
		if (n != N) ans += n-pos+1, pre[n] = p;
		if (p != -1) nex[p] = n;
	}
} 
void add_contribution_alt(const vector<int>& h) {
	stack<int> stk;
	for (int i = N-1; i >= 0; --i) {
		while (!stk.empty() && h[stk.top()] < h[i]) stk.pop();
		if (!stk.empty()) ans += stk.top()-i+1;
		stk.push(i);
	}
}

int main() { 
	cin >> N;
	vector<int> h(N); for (int& i: h) cin >> i;
	add_contribution(h);
	reverse(begin(h), end(h));
	add_contribution(h);
	cout << ans;
}

 

#include <bits/stdc++.h>
using namespace std;
struct edge {
    int cow;  
    int to;
    bool is_first;
 
    edge() {};
    edge(int cow, int to, bool is_first) : cow(cow), to(to), is_first(is_first) {};
};
vector<edge> adj[100001];
bool visited_cycle[100001];  
bool visited[100001]; 
bool gets_cereal[100001]; 
int hungry_cows = 0;
queue<int> order;
int ignore_edge = -1,N,M,first_cereal = -1;  
 
void find_cycle(int cur, int prev = -1) {
    visited_cycle[cur] = true; 
 
    for (edge next : adj[cur]) {
        if (visited_cycle[next.to]) {
            if (first_cereal == -1 && next.to != prev) {
                if (next.is_first) {
                    first_cereal = next.to; 
                } else {
                    first_cereal = cur;
                }
                
                ignore_edge = next.cow; 
                order.push(next.cow);
                gets_cereal[next.cow] = true;
            }
        } else {
            find_cycle(next.to, cur);
        }
    }
}
 
 
void dfs(int cur) {
    visited[cur] = true;
    for (edge next : adj[cur]) {
        if (!visited[next.to] && next.cow != ignore_edge) { 
            gets_cereal[next.cow] = true;
            order.push(next.cow);
            dfs(next.to);
        }
    }
}
 
 
int main() {
    cin >> N >> M;
    for (int i = 0; i < N; ++i) {
        int a, b;
        cin >> a >> b;
        adj[a].push_back(edge(i+1, b, false));
        adj[b].push_back(edge(i+1, a, true));
    }
 
    for (int i = 1; i <= M; ++i) {
        first_cereal = -1;
        ignore_edge = -1;
        if (!visited[i]) {
            find_cycle(i);
           
            if (first_cereal > 0) {
                dfs(first_cereal);
            } else {
                dfs(i);
            }
        }
    }
 
    for (int i = 1; i <= N; ++i) {
        if (!gets_cereal[i]) {
            ++hungry_cows;
            order.push(i);
        } 
    }
 
    cout << hungry_cows << endl;
    while (!order.empty()) {
        cout << order.front() << endl; 
        order.pop();
    }
    return 0;
}