牛客练习赛11Btrie树+拓扑判环E分治求平面最近点对

#include
using namespace std;
#pragma comment(linker, "/STACK:102400000,102400000")
#define rep(i,a,b) for (int i=a; i<=b; ++i)
#define per(i,b,a) for (int i=b; i>=a; --i)
#define mes(a,b)  memset(a,b,sizeof(a))
#define INF 0x3f3f3f3f
#define MP make_pair
#define PB push_back
#define fi  first
#define se  second
typedef long long ll;
const int N = 30005, M = 300005;

int n, cnt, tr[M][26], val[M*26];
string s[N];
void Insert(int ci)
{
    int len=s[ci].size(), now=0;
    rep(j,0,len-1)
    {
        int tmp=s[ci][j]-'a';
        if(tr[now][tmp]==0) tr[now][tmp]=++cnt;
        now = tr[now][tmp];
    }
    ++val[now];
}
vector<int > G[26];
int in[26];
queue<int > q;
bool Toposort()
{
    rep(i,0,25) if(in[i]==0) q.push(i);
    while(!q.empty())
    {
        int u=q.front(); q.pop();
        for(int i=0; ii)
        {
            --in[G[u][i]];
            if(in[G[u][i]]==0) q.push(G[u][i]);
        }
    }
    rep(i,0,25) if(in[i]) return false;
    return true;
}
bool check(int ci)
{
    rep(i,0,25) G[i].clear(), in[i]=0;
    int len=s[ci].size(), now=0;
    rep(j,0,len-1)
    {
        int tmp=s[ci][j]-'a';
        if(j1 && val[tr[now][tmp]]) return false;
        rep(i,0,25) {
            if(tr[now][i] && i!=tmp)
                G[tmp].PB(i), ++in[i];
        }
        now = tr[now][tmp];
    }
    if(Toposort()) return true;
    return false;
}
int ans[N], ans1;
int main()
{
    scanf("%d", &n);
    rep(i,1,n)
    {
        cin>> s[i];
        Insert(i);
    }
    rep(i,1,n)
    {
        if(check(i)) ans[++ans1]=i;
    }
    printf("%d\n", ans1);
    rep(i,1,ans1)
        cout<endl;

    return 0;
}

// E
#include
using namespace std;
#pragma comment(linker, "/STACK:102400000,102400000")
#define rep(i,a,b) for (int i=a; i<=b; ++i)
#define per(i,b,a) for (int i=b; i>=a; --i)
#define mes(a,b)  memset(a,b,sizeof(a))
#define INF 0x3f3f3f3f
#define MP make_pair
#define PB push_back
#define fi  first
#define se  second
typedef long long ll;
const int N = 100005;

struct Point { double x, y; };
struct Point point[N], *px[N], *py[N];
double get_dis(Point *p1,Point *p2) {
    return sqrt((p1->x-p2->x)*(p1->x-p2->x)+(p1->y-p2->y)*(p1->y-p2->y));
}
bool cmpx(Point *p1,Point *p2) { return p1->xx; }
bool cmpy(Point *p1,Point *p2) { return p1->yy; }
double min(double a,double b) { return aa:b; }
double closest(int s,int e)
{
    if(s+1==e)
        return get_dis(px[s],px[e]);
    if(s+2==e)
        return min(get_dis(px[s],px[s+1]),min(get_dis(px[s+1],px[e]),get_dis(px[s],px[e])));
    int mid=(s+e)>>1;
    double ans=min(closest(s,mid),closest(mid+1,e));//递归求解
    int i, j, cnt=0;
    for(i=s; i<=e; i++)//把x坐标在px[mid].x-ans~px[mid].x+ans范围内的点取出来
    {
        if(px[i]->x>=px[mid]->x-ans && px[i]->x<=px[mid]->x+ans)
            py[cnt++]=px[i];
    }
    sort(py, py+cnt, cmpy);//按y坐标排序
    for(i=0; i)
    {
        for(j=i+1;j//py数组中的点是按照y坐标升序的
        {
            if(py[j]->y-py[i]->y>=ans)  break;
            ans=min(ans,get_dis(py[i],py[j]));
        }
    }
    return ans;
}
/*void Init()
{
    for(int i=1; i<=n; ++i) {
        scanf("%lf%lf", &point[i].x, &point[i].y);
        px[i] = &point[i];
    }
    sort(px+1, px+1+n);
}*/

int n;
double ai, sum[N];
int main()
{
    scanf("%d", &n);
    rep(i,1,n)
    {
        scanf("%lf", &ai);
        sum[i]=sum[i-1]+ai;
        point[i].x=1.0*i, point[i].y=sum[i];
        px[i] = &point[i];
    }
    sort(px+1, px+1+n, cmpx);
    double ans = closest(1, n);
    printf("%.0f\n", ans*ans);

    return 0;
}