2019 ICPC 南京 网络赛

 

solve : 3/10

补题 : 5/10


https://www.jisuanke.com/contest/3004?view=challenges

A、The beautiful values of the palace

开场先开A,开了一眼这曲线不是去年蓝桥杯省赛的题吗,然后随便判了一下(大概15分钟)把值求出来了。

然后开始思考用线段树来实现nlogn,,因为 数据范围 看上去需要离散化,然后因为一开始只离散化了  个数字,然后upper_bound去找,然后又发现这样会找到 0 的情况(通过整体+1处理掉了)以及特别大的查询数字会被离散化为最后一个点的值,然后在离散化的地方Debug了巨久

写了一个半小时,Debug完了,队友怂恿我交一发,WA了,然后改成了  个值直接离散化,还是WA了,这个时候其实心态有点爆炸?我感觉A是个简单题,但实际上当时过的人并不多?以至于我觉得自己想了个假算法?

然后发现F题过的挺多的,随便推了一下,发现是个裸的主席树?(太假了,应该先直接开F

后期演了一波说这个线段树有问题,不能这样做。然后全队跑去开B。(其实是因为我使用的方法有问题。


感觉在决定要离散化的时候正常比赛就完了啊,离散化  也太恶心了啊,后面出现 1 1 3 3,这个询问被离散化为1 1 1 1,然后就改  ,然后整个人就死在处理离散化的路上了。

今天上午补了一波题,将线段树做法修正后,爆炸WA,然后看了一眼老哥代码,???

这个值等于数位和?不是,我不等于数位和为啥过了样例啊。原来最大的问题不是线段树,然后把第一发错误代码拉过来交了一下。居然过了,太假了

没有离散化的代码:

正确通过 2019-09-02 10:48 1148ms 102728kB c++
#include <bits/stdc++.h>
#define ll long long
#define sc scanf
#define pr printf
#define lson left,mid,k<<1
#define rson mid+1,right,k<<1|1
#define imid int mid=(left+right)/2;
using namespace std;
ll n, m, q;
ll gets(ll xx, ll yy)
{
	ll x = -yy, y = -xx;
	if (x >= 0)
	{
		if (y >= 0)
		{
			if (y >= x)
				return 4 * y * y - y + x + 1;
			else
				return 4 * x * x + x - y + 1;
		}
		else
		{
			if (y >= -x)
				return (2 * x + 1) * (2 * x) - x - y + 1;
			else
				return (1 - 2 * y) * (2 * (-y)) - x - y + 1;
		}
	}
	else
	{
		if (y >= 0)
		{
			if (y >= -x)
				return (2 * y) * (2 * y - 1) + x + y + 1;
			else
				return (2 * (-x)) * (2 * (-x) - 1) + x + y + 1;
		}
		else
		{
			if (y >= x + 1)
				return (-1 - 2 * x) * (-1 - 2 * x) - x - 1 + y + 1;
			else
				return (1 - 2 * y) * (1 - 2 * y) - x - 1 + y + 1;
		}
	}
}
ll get(ll x, ll y)
{
	return n * n - gets(x - (n + 1) / 2, y - (n + 1) / 2) + 1;
}
ll gg(ll num)
{
	ll res = 0;
	while (num)
	{
		res += num % 10;
		num /= 10;
	}
	return res;
}

const int MAXN = 1e6 + 5;

struct node
{
	int l;
	int r;
	ll sum;
}que[1000010 * 4];
int ql, qr;
ll val;
void up(int k)
{
	que[k].sum = que[k << 1].sum + que[k << 1 | 1].sum;
}
void build(int left = 1, int right = MAXN, int k = 1)
{
	que[k].l = left;
	que[k].r = right;
	que[k].sum = 0;
	if (left == right)
		return;
	imid;
	build(lson);
	build(rson);
}
void update(int left = 1, int right = MAXN, int k = 1)
{
	if (qr < left || right < ql)
		return;
	if (ql <= left && right <= qr)
	{
		que[k].sum = que[k].sum + val;
		return;
	}
	imid;
	update(lson);
	update(rson);
	up(k);
}
ll query(int left = 1, int right = MAXN, int k = 1)
{
	if (qr < left || right < ql)
		return 0;
	if (ql <= left && right <= qr)
		return que[k].sum;
	imid;
	return query(lson) + query(rson);
}

struct note
{
	ll x;
	ll y;
	ll num;
}a[500005];

struct qq
{
	ll x1;
	ll y1;
	ll x2;
	ll y2;
}in[100005];

int cnt;
#define Pair pair<int,int>
int main()
{
	int T;
	sc("%d", &T);
	while (T--)
	{
		map<Pair, ll>mp;
		sc("%d%d%d", &n, &m, &q);
		cnt = 0;
		for (int i = 0; i < m; i++)
		{
			sc("%lld%lld", &a[i].x, &a[i].y);
			a[i].num = get(a[i].x, a[i].y);
			a[i].num = gg(a[i].num);
		}
		cnt = m;
		for (int i = 0; i < q; i++)
		{
			sc("%lld%lld%lld%lld", &in[i].x1, &in[i].y1, &in[i].x2, &in[i].y2);
			a[cnt++] = note{ in[i].x1 - 1, in[i].y1 - 1, 0 };
			a[cnt++] = note{ in[i].x2, in[i].y2, 0 };
			a[cnt++] = note{ in[i].x1 - 1, in[i].y2, 0 };
			a[cnt++] = note{ in[i].x2, in[i].y1 - 1, 0 };
		}

		sort(a, a + cnt, [](note q, note w) {
			if (q.x == w.x)
			{
				if (q.y == w.y)
					return q.num > w.num;
				else
					return q.y < w.y;
			}
			return q.x < w.x;
			});
		build();
		for (int i = 0; i < cnt; i++)
		{
			if (a[i].num == 0)
			{
				ql = 1, qr = a[i].y;
				ll ans = query();
				mp[Pair{ a[i].x,a[i].y }] = ans;
			}
			else
			{
				ql = qr = a[i].y, val = a[i].num;
				update();
			}
		}
		for (int i = 0; i < q; i++)
		{
			ll ans = mp[Pair{ in[i].x2,in[i].y2 }] - mp[Pair{ in[i].x1 - 1,in[i].y2 }] - mp[Pair{ in[i].x2,in[i].y1 - 1 }] + mp[Pair{ in[i].x1 - 1,in[i].y1 - 1 }];
			pr("%lld\n", ans);
		}
	}
}

离散化的代码:

正确通过 2019-09-02 10:44 1440ms 81632kB c++
#include <bits/stdc++.h>
#define ll long long
#define sc scanf
#define pr printf
#define lson left,mid,k<<1
#define rson mid+1,right,k<<1|1
#define imid int mid=(left+right)/2;
using namespace std;
ll n, m, q;
ll gets(ll xx, ll yy)
{
	ll x = -yy, y = -xx;
	if (x >= 0)
	{
		if (y >= 0)
		{
			if (y >= x)
				return 4 * y * y - y + x + 1;
			else
				return 4 * x * x + x - y + 1;
		}
		else
		{
			if (y >= -x)
				return (2 * x + 1) * (2 * x) - x - y + 1;
			else
				return (1 - 2 * y) * (2 * (-y)) - x - y + 1;
		}
	}
	else
	{
		if (y >= 0)
		{
			if (y >= -x)
				return (2 * y) * (2 * y - 1) + x + y + 1;
			else
				return (2 * (-x)) * (2 * (-x) - 1) + x + y + 1;
		}
		else
		{
			if (y >= x + 1)
				return (-1 - 2 * x) * (-1 - 2 * x) - x - 1 + y + 1;
			else
				return (1 - 2 * y) * (1 - 2 * y) - x - 1 + y + 1;
		}
	}
}
ll gg(ll num)
{
	ll res = 0;
	while (num)
	{
		res += num % 10;
		num /= 10;
	}
	return res;
}
ll get(ll x, ll y)
{
	return n * n - gets(x - (n + 1) / 2, y - (n + 1) / 2) + 1;
}

struct node
{
	int l;
	int r;
	ll sum;
}que[500010 * 4];
int ql, qr;
ll val;
void up(int k)
{
	que[k].sum = que[k << 1].sum + que[k << 1 | 1].sum;
}
void build(int left = 1, int right = 500005, int k = 1)
{
	que[k].l = left;
	que[k].r = right;
	que[k].sum = 0;
	if (left == right)
		return;
	imid;
	build(lson);
	build(rson);
}
void update(int left = 1, int right = 500005, int k = 1)
{
	if (qr < left || right < ql)
		return;
	if (ql <= left && right <= qr)
	{
		que[k].sum = que[k].sum + val;
		return;
	}
	imid;
	update(lson);
	update(rson);
	up(k);
}
ll query(int left = 1, int right = 500005, int k = 1)
{
	if (qr < left || right < ql)
		return 0;
	if (ql <= left && right <= qr)
		return que[k].sum;
	imid;
	return query(lson) + query(rson);
}

struct in
{
	ll x;
	ll y;
	ll num;
}a[500005];

struct qq
{
	ll x1;
	ll y1;
	ll x2;
	ll y2;
}qqq[100005];

ll qwe[100005][8];

int tx[500005], ty[500005];
int qqa, qqb, cnta, cntb, cnt;
void add(ll x, ll y)
{
	a[cnt++] = in{ x,y,0 };
}
#define Pair pair<int,int>
int main()
{
	int T;
	sc("%d", &T);
	while (T--)
	{
		map<Pair, ll>mp;
		sc("%d%d%d", &n, &m, &q);
		cnta = 0, cntb = 0;
		cnt = 0;
		for (int i = 0; i < m; i++)
		{
			sc("%lld%lld", &a[i].x, &a[i].y);
			a[i].num = gg(get(a[i].x, a[i].y));
			tx[cnta++] = a[i].x;
			ty[cntb++] = a[i].y;
		}
		cnt = m;
		for (int i = 0; i < q; i++)
		{
			sc("%lld%lld%lld%lld", &qqq[i].x1, &qqq[i].y1, &qqq[i].x2, &qqq[i].y2);
			tx[cnta++] = qqq[i].x1 - 1;
			tx[cnta++] = qqq[i].x2;
			ty[cntb++] = qqq[i].y1 - 1;
			ty[cntb++] = qqq[i].y2;
			/*add(qqq[i].x1 - 1, qqq[i].y1 - 1);
			add(qqq[i].x2, qqq[i].y2);
			add(qqq[i].x1 - 1, qqq[i].y2);
			add(qqq[i].x2, qqq[i].y1 - 1);
			qqq[i].x1 = upper_bound(tx, tx + qqa, qqq[i].x1) - tx + 1;
			qqq[i].x2 = upper_bound(tx, tx + qqa, qqq[i].x2) - tx + 1;
			qqq[i].y1 = upper_bound(ty, ty + qqb, qqq[i].y1) - ty + 1;
			qqq[i].y2 = upper_bound(ty, ty + qqb, qqq[i].y2) - ty + 1;*/
		}
		//a[cnt++] = in{ x,y,0 };
		sort(tx, tx + cnta);
		sort(ty, ty + cntb);
		qqa = unique(tx, tx + cnta) - tx;
		qqb = unique(ty, ty + cntb) - ty;
		for (int i = 0; i < m; i++)
		{
			a[i].x = lower_bound(tx, tx + qqa, a[i].x) - tx + 1;
			a[i].y = lower_bound(ty, ty + qqb, a[i].y) - ty + 1;
		}
		for (int i = 0; i < q; i++)
		{
			int q1 = lower_bound(tx, tx + qqa, qqq[i].x1 - 1) - tx + 1;
			int w1 = lower_bound(ty, ty + qqb, qqq[i].y1 - 1) - ty + 1;
			qwe[i][0] = q1;
			qwe[i][1] = w1;
			a[cnt++] = in{ q1,w1,0 };
			q1 = lower_bound(tx, tx + qqa, qqq[i].x2) - tx + 1;
			w1 = lower_bound(ty, ty + qqb, qqq[i].y1 - 1) - ty + 1;
			qwe[i][2] = q1;
			qwe[i][3] = w1;
			a[cnt++] = in{ q1,w1,0 };
			q1 = lower_bound(tx, tx + qqa, qqq[i].x1 - 1) - tx + 1;
			w1 = lower_bound(ty, ty + qqb, qqq[i].y2) - ty + 1;
			qwe[i][4] = q1;
			qwe[i][5] = w1;
			a[cnt++] = in{ q1,w1,0 };
			q1 = lower_bound(tx, tx + qqa, qqq[i].x2) - tx + 1;
			w1 = lower_bound(ty, ty + qqb, qqq[i].y2) - ty + 1;
			qwe[i][6] = q1;
			qwe[i][7] = w1;
			a[cnt++] = in{ q1,w1,0 };
		}

		sort(a, a + cnt, [](in q, in w) {
			if (q.x == w.x)
			{
				if (q.y == w.y)
					return q.num > w.num;
				else
					return q.y < w.y;
			}
			return q.x < w.x;
			});
		build();
		for (int i = 0; i < cnt; i++)
		{
			if (a[i].num == 0)
			{
				ql = 1, qr = a[i].y;
				ll ans = query();
				mp[Pair{ a[i].x,a[i].y }] = ans;
			}
			else
			{
				ql = qr = a[i].y, val = a[i].num;
				update();
			}
		}
		for (int i = 0; i < q; i++)
		{
			ll ans = mp[Pair{ qwe[i][6],qwe[i][7] }] - mp[Pair{ qwe[i][2],qwe[i][3] }] - mp[Pair{ qwe[i][4],qwe[i][5] }] + mp[Pair{ qwe[i][0],qwe[i][1] }];
			pr("%lld\n", ans);
		}
	}
}

B、super_log

求   (b个a)。

欧拉降幂

欧拉定理:

降幂公式:

  

其中,第一个公式要求 a 和 mod 互质,第二第三个公式不要求 a mod 互质。


所以只要先搞最高次幂,递归就可以了,赛时快速幂没写欧拉降幂。

#include <bits/stdc++.h>
#define ll long long
#define sc scanf
#define pr printf
using namespace std;
ll power(ll a, ll b, ll mod)
{
	ll res = 1;
	while (b)
	{
		if (b & 1)
		{
			res = res * a;
			if (res >= mod)
				res = res % mod + mod;
		}
		a = a * a;
		if (a >= mod)
			a = a % mod + mod;
		b >>= 1;
	}
	return res;
}
ll phi(ll n)
{
	ll res = n;
	for (ll i = 2; i * i <= n; i++)
	{
		if (n % i == 0)
		{
			res = res - res / i;
			while (n % i == 0)
				n /= i;
		}
	}
	if (n > 1)
		res = res - res / n;
	return res;
}
ll dfs(ll n, ll m, ll cnt)
{
	if (m == 1)
	{
		if (n == 0)
			return 0;
		else
			return 1;
	}
	if (cnt == 1)
	{
		if (n >= m)
			return n % m + m;
		return n;
	}
	return power(n, dfs(n, phi(m), cnt - 1), m);
}
int main()
{
	int T;
	sc("%d", &T);
	while (T--)
	{
		ll a, b, mod;
		sc("%lld%lld%lld", &a, &b, &mod);
		if (b == 0)
		{
			pr("%lld\n", 1 % mod);
			continue;
		}
		else if (b == 1)
		{
			pr("%lld\n", a % mod);
			continue;
		}
		else
		{
			b--;
			ll ans = dfs(a, phi(mod), b);
			ans = power(a, ans, mod);
			pr("%lld\n", ans % mod);
		}
	}
}

F、Greedy Sequence

排个序,从小遍历到大,然后求一下这个数字在当前区间的个数k,然后求区间k-1小的值,然后转移

int id[MAXN];
int ans[MAXN];
int main()
{
	int T;
	sc("%d", &T);
	while (T--)
	{
		scanf("%d%d", &n, &m);
		for (int i = 1; i <= n; i++)
		{
			scanf("%d", &a[i]);
			t[i] = a[i];
			id[a[i]] = i;
			ans[i] = 0;
		}
		sort(t + 1, t + 1 + n);
		int qq = unique(t + 1, t + 1 + n) - t - 1;
		for (int i = 1; i <= n; i++)
			a[i] = lower_bound(t + 1, t + qq + 1, a[i]) - t;
		init();
		for (int i = 1; i <= n; i++)
		{
			root[i] = root[i - 1];
			build(a[i], root[i], 1, n);
		}
		int ql, qr, k;
		for (int i = 1; i <= n; i++)
		{
			ql = max(id[i] - m, 1);
			qr = min(id[i] + m, n);
			int tot = querycnt(root[ql - 1], root[qr], 1, i, 1, n);
			k = tot - 1;
			if (k == 0)
			{
				ans[i] = 1;
			}
			else
			{
				int pos = query(root[ql - 1], root[qr], k, 1, n);
				ans[i] = ans[pos] + 1;
			}
		}
		for (int i = 1; i <= n; i++)
			pr("%d%c", ans[i], i == n ? '\n' : ' ');
	}
}

H、Holy Grail

#include<queue>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define N 10005
#define M 20005
using namespace std;
typedef long long ll;
const ll INF = 1e12;
ll n,m,t;
ll v[M],w[M],nextt[M];
ll d[N],cnt[N],first[N];
bool vis[N];
void add(ll x,ll y,ll z)
{
        t++;
        nextt[t]=first[x];
        first[x]=t;
        v[t]=y;
        w[t]=z;
}
bool SPFA(ll s)
{
        ll x,y,i,j;
        queue<ll>q;
        for(int i=0;i<=n;++i) d[i]=INF,vis[i]=false;
//        memset(d,127,sizeof(d));
//        memset(vis,false,sizeof(vis));
        while(!q.empty())  q.pop();
        d[s]=0;
        cnt[s]=1;
        q.push(s);
        vis[s]=true;
        while(!q.empty())
        {
                x=q.front();
                q.pop();
                vis[x]=false;
                for(i=first[x];i;i=nextt[i])
                {
                        y=v[i];
                        if(d[y]>d[x]+w[i])
                        {
                                d[y]=d[x]+w[i];
                                cnt[y]=cnt[x]+1;
                                if(cnt[y]>n)
                                  return false;
                                if(!vis[y])
                                {
                                        q.push(y);
                                        vis[y]=true;
                                }
                        }
                }
        }
        return true;
}
int main()
{
	ll T;
	scanf("%lld",&T);
	while(T--){
		ll x,y,z,i;
        scanf("%lld%lld",&n,&m);
        for(int i=0;i<=n;++i) first[i]=0;
        t=0;
        for(i=1;i<=m;++i)
        {
	        scanf("%lld%lld%lld",&x,&y,&z);
            add(x,y,z);
        }
        for(int i=1;i<=6;++i){
        	ll a,b;
        	scanf("%lld%lld",&a,&b);
        	ll c = -INF;
        	add(a,b,c);
        	ll l = -2e12,r = 1e12;
        	ll ans;
        	while(l+1<r){
        		ll mid = (l+r)>>1;
        		w[t]=mid;
        		if(!SPFA(b)) l=mid;
				else r=mid;
			}
			w[t]=l;
			if(!SPFA(b))
				ans=r;
			else ans=l;
			printf("%lld\n",ans);
			w[t]=ans;
		}
	}
	return 0;
}

 

 

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