43 lines
973 B
C++
43 lines
973 B
C++
#include <bits/stdc++.h>
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using namespace std;
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const int N = 2e5 + 10;
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const int INF = 0x3f3f3f3f;
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int n, k;
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int q[N];
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int dist[N];
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int Min = INF;
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int bfs() {
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//初始化距离数组-1
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memset(dist, -1, sizeof dist);
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int hh = 0, tt = -1;
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q[++tt] = n; //加入起点n
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dist[n] = 0; // n距离出发点0个长度
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while (hh <= tt) {
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int t = q[hh++];
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if (t == k) return dist[k];
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if (t + 1 < N && dist[t + 1] == -1) {
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dist[t + 1] = dist[t] + 1;
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q[++tt] = t + 1;
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}
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if (t - 1 >= 0 && dist[t - 1] == -1) {
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dist[t - 1] = dist[t] + 1;
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q[++tt] = t - 1;
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}
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if (t * 2 < N && dist[t * 2] == -1) {
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dist[t * 2] = dist[t] + 1;
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q[++tt] = t * 2;
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}
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}
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return 0;
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}
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int main() {
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//农夫起始位于点N，牛位于点K
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cin >> n >> k;
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printf("%d\n", bfs());
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return 0;
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}
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