题解 | #求x到y的最少计算次数# bfs

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

int x, y;
stack<int> st;
int s[201];

int main() {
    scanf("%d,%d", &x, &y);
    if(x == y){
        cout << 0 << endl;
        return 0;
    }
    int d = 0;
    st.push(x);
    s[x + 100] = 1;
    //出栈
    while (st.size()) {
        d ++;
        vector<int> tmp;
        // printf("d=%d\n",d);
        while (st.size()) {
            int t = st.top();
            // printf("%d ", t);
            st.pop();
            tmp.push_back(t);
        }
        // printf("\n");
        for (int tt : tmp) {
            for (int i = 0; i < 3; i++) {
                int a = tt + 1;
                if (a == y) {
                    cout << d << endl;
                    return 0;
                }
                if (s[a + 100] == 0) {
                    st.push(a);
                    s[a + 100] = 1;
                }

                a = tt - 1;
                if (a == y) {
                    cout << d << endl;
                    return 0;
                }
                if (s[a + 100] == 0) {
                    st.push(a);
                    s[a + 100] = 1;
                }

                a = tt * 2;
                if (a == y) {
                    cout << d << endl;
                    return 0;
                }
                if (s[a + 100] == 0) {
                    st.push(a);
                    s[a + 100] = 1;
                }

            }
        }
    }

    return 0;
}
// 64 位输出请用 printf("%lld")