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47 lines
1.1 KiB
47 lines
1.1 KiB
#include <bits/stdc++.h>
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using namespace std;
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typedef pair<int, int> PII;
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const int N = 1010;
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int n, m;
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queue<PII> q;
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int st[N];
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//检查是不是出界
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bool check(int pos) {
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if (pos < 1 || pos > 1000) return false;
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return true;
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}
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void bfs() {
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//形成一个数对放入队列
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q.push({n, 0});
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//套路
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while (q.size()) {
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PII x = q.front();
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q.pop();
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if (x.first == m) {
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cout << x.second << endl;
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break;
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}
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if (!st[x.first + 1]) {
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if (!check(x.first + 1)) continue;
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q.push({x.first + 1, x.second + 1});
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st[x.first + 1] = 1;
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}
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if (!st[x.first - 1]) {
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if (!check(x.first - 1)) continue;
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q.push({x.first - 1, x.second + 1});
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st[x.first - 1] = 1;
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}
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if (!st[x.first * 2]) {
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if (!check(x.first * 2)) continue;
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q.push({x.first * 2, x.second + 1});
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st[x.first * 2] = 1;
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}
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}
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}
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int main() {
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cin >> n >> m;
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bfs();
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return 0;
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} |