python/TangDou/AcWing/IDAstar/180_Test.cpp

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
const int N = 20;
int q[N];
int g[10][N];
int n;

int f() {
    int tot = 0;
    for (int i = 1; i <= n - 1; i++)
        if (q[i] + 1 != q[i + 1])
            tot++;

    return (tot + 2) / 3;
}
bool panduan() {
    for (int i = 1; i <= n; i++)
        if (q[i] != i)
            return false;
    return true;
}
bool dfs(int u, int depth) {
    if (u + f() > depth) return false;

    if (panduan()) {
        return true;
    }
    for (int len = 1; len < n; len++)
        for (int qi1 = 1; qi1 + len - 1 <= n; qi1++) {
            int r = qi1 + len;
            for (int wai = r; wai <= n; wai++) {
                memcpy(g[u], q, sizeof q);
                //   memccpy(g[u],q,sizeof q);
                int i, j;
                for (i = qi1, j = r; j <= wai; i++, j++)
                    q[i] = g[u][j];
                for (j = qi1; j <= qi1 + len - 1; i++, j++)
                    q[i] = g[u][j];
                if (dfs(u + 1, depth)) {
                    return true;
                }
                memcpy(q, g[u], sizeof g[u]);
            }
        }

    return false;
}

int main() {
    freopen("180.in", "r", stdin);

    // 记录开始时间
    clock_t begin = clock();

    int T;
    scanf("%d", &T);
    while (T--) {
        scanf("%d", &n); // 表示书的数量
        for (int i = 1; i <= n; i++) scanf("%d", &q[i]);

        int depth = 0;
        while (depth < 5 && !dfs(0, depth)) depth++;
        // while (depth <= 5 && !dfs(0, depth)) depth++;
        // 会有1个测试点超时
        // 提醒我们：在使用迭代加深时，要严格注意depth的边界范围
        if (depth < 5)
            cout << depth << endl;
        else
            cout << "5 or more" << endl;
    }

    // 记录结束时间
    clock_t end = clock();
    cout << "Running time:" << (double)(end - begin) / CLOCKS_PER_SEC * 1000 << "ms" << endl;

    return 0;
}