41 lines
945 B
C++
41 lines
945 B
C++
#include <bits/stdc++.h>
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using namespace std;
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const int N = 100000, M = N + 10;
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struct Node {
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int pos;
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int step;
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};
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bool st[M];
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int main() {
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int n, k; //农夫位置，牛的位置
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cin >> n >> k;
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queue<Node> q;
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q.push({n, 0}); //农夫位置，步数
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st[n] = true;
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while (q.size()) {
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auto t = q.front();
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q.pop();
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//出口
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if (t.pos == k) {
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cout << t.step << endl;
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break;
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}
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if (t.pos + 1 <= N && !st[t.pos + 1]) {
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q.push({t.pos + 1, t.step + 1});
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st[t.pos + 1] = true;
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}
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if (t.pos - 1 >= 0 && !st[t.pos - 1]) {
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q.push({t.pos - 1, t.step + 1});
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st[t.pos - 1] = true;
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}
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if (t.pos * 2 <= N && !st[t.pos * 2]) {
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q.push({t.pos * 2, t.step + 1});
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st[t.pos * 2] = true;
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}
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}
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return 0;
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}
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