CF 101196 G That’s One Hanoi-ed Teacher

That’s One Hanoi-ed Teacher

链接

题意：

　　询问一个汉诺塔的状态是否是最优的状态，如果是，询问还有多少步到最终状态。

分析：

　　考虑汉诺塔是怎么操作的，首先是A->

代码：

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iostream>
#include<cmath>
#include<cctype>
#include<set>
#include<queue>
#include<vector>
#include<map>
using namespace std;
typedef long long LL;

inline int read() {
    int x=0,f=1;char ch=getchar();for(;!isdigit(ch);ch=getchar())if(ch=='-')f=-1;
    for(;isdigit(ch);ch=getchar())x=x*10+ch-'0';return x*f;
}

LL ans = 0;
bool dfs(int now,vector<int>& A, vector<int> &B, vector<int> &C) {
    if (!now) return 1;
    if (A.size() && A[0] == now) {
        ans += 1ll << (now - 1);
        A.erase(A.begin());
        return dfs(now - 1, A, C, B);
    }
    if (C.size() && C[0] == now) {
        C.erase(C.begin());
        return dfs(now - 1, B, A, C);
    }
    return 0;
} 
vector<int> A, B, C;

int main() {
    int a = read();
    for (int i = 1; i <= a; ++i) A.push_back(read());
    int b = read();
    for (int i = 1; i <= b; ++i) B.push_back(read());
    int c = read();
    for (int i = 1; i <= c; ++i) C.push_back(read());
    if (!dfs(a + b + c, A, B, C)) puts("No"); 
    else printf("%lld\n", ans);
    return 0;
}