寒假刷题第14天

PTA甲级

1089 Insert or Merge

插入排序：前半部分有序后半部分无序

归并排序：每一个小序列是有序的

#include
#include
#include

using namespace std;

int n;
vectorlast , now;

bool check()
{
    for(int i = now.size() - 1;i >= 0;i --)
    {
        if(now[i] != last[i]) 
        {
            if(i >= 0)
            {
                if(now[i - 1] > now[i]) return false;
            }
        }
    }
    return true;
}

void merge()
{
    puts("Merge Sort");
    bool f = 0;
    for (int step = 2;step / 2 < n;step *= 2) 
    {
        for(int i = 0;i < n;i += step) 
            sort(last.begin() + i , last.begin() + min(i + step, n));
        if (f) 
        {
            cout << last[0];
            for (int k = 1; k < n;k ++) cout << " " << last[k];
            break;
        }
        if (last == now) f = 1;
    }
}

void Insert()
{
    puts("Insertion Sort");
    bool f = 0;
    for(int i = 2;i <= n;i ++)
    {
        sort(last.begin() , last.begin() + i);
        if(f)
        {
            for(int i = 0;i < n;i ++)
            {
                if(i) cout << " ";
                cout << last[i];
            }
            break;
        }
        if(last == now) f = 1;
    }
}

int main()
{
    cin >> n;
    for(int i = 0;i < n;i ++)
    {
        int x;
        cin >> x;
        last.push_back(x);
    }

    for(int i = 0;i < n;i ++)
    {
        int x;
        cin >> x;
        now.push_back(x);
    }
    if(check()) Insert();
    else merge();
    return 0;
}

1091 Acute Stroke

三维广搜

#include
#include
#include
#include

using namespace std;

const int N = 1e5 + 10;
int m , n , l , t;
int g[60][200][200];
bool st[60][200][200];
int res = 0;
int dx[6] = {0 , 0 , 1 , -1 , 0 , 0};
int dy[6] = {1 , -1 , 0 , 0 , 0 , 0};
int dz[6] = {0 , 0 , 0 , 0 , 1 , -1};

struct point
{
    int x , y , z;
};

void bfs(point p)
{
    queueq;
    q.push(p);
    int w = 0;
    st[p.z][p.x][p.y] = true;
    while(!q.empty())
    {
        auto t = q.front();
        q.pop();
        st[t.z][t.x][t.y] = true;
        w ++;
        for(int i = 0;i < 6;i ++)
        {
            int tx = t.x + dx[i] , ty = t.y + dy[i] , tz = t.z + dz[i];
            if(tx < 0 || tx >= m || ty < 0 || ty >= n || tz < 0 || tz >= l) continue;
            if(st[tz][tx][ty] || !g[tz][tx][ty]) continue;
            st[tz][tx][ty] = true;
            q.push({tx , ty , tz});
        }
    }
    if(w >= t) res += w;
}

int main()
{
    memset(st , 0 , sizeof st);
    cin >> m >> n >> l >> t;
    for(int i = 0;i < l;i ++)
        for(int j = 0;j < m;j ++)
            for(int h = 0;h < n;h ++)
                cin >> g[i][j][h];
    for(int i = 0;i < l;i ++)
        for(int j = 0;j < m;j ++)
            for(int h = 0;h < n;h ++)
                if(!st[i][j][h] && g[i][j][h])
                {
                    point p = {j , h , i};
                    bfs(p);
                }
    cout << res << endl;
    return 0;
}

1099 Build A Binary Search Tree

dfs+bfs

#include
#include
#include
#include
#include

using namespace std;

const int N = 110;
int n;
int l[N] , r[N] , w[N];
int tree_w[N] , cnt = 0;

void dfs(int u)
{
    if(l[u] != -1) dfs(l[u]);
    tree_w[u] = w[cnt ++];
    if(r[u] != -1) dfs(r[u]);
}

int main()
{
    memset(l , -1 , sizeof l);
    memset(r , -1 , sizeof r);
    cin >> n;
    for(int i = 0;i < n;i ++)
    {
        int x , y;
        cin >> x >> y;
        if(x != -1) l[i] = x;
        if(y != -1) r[i] = y;
    }
    for(int i = 0;i < n;i ++) cin >> w[i];
    sort(w , w + n);
    dfs(0);
    queueq;
    bool is_first = true;
    q.push(0);
    while(!q.empty())
    {
        int t = q.front();
        q.pop();
        if(!is_first) cout << " ";
        is_first = false;
        cout << tree_w[t];
        if(l[t] != -1) q.push(l[t]);
        if(r[t] != -1) q.push(r[t]);
    }
    return 0;
}

1095 Cars on Campus

多亏了柳神，我才能写出来，真恶心的模拟

#include 
#include 
#include 
#include 
#include 
#include