• Codeforces 216D Spider's Web 树状数组+模拟


    题目链接:http://codeforces.com/problemset/problem/216/D

    题意:

    对于一个梯形区域,假设梯形左边的点数!=梯形右边的点数,那么这个梯形为红色。否则为绿色,

    问:

    给定的蜘蛛网中有多少个红色。

    2个树状数组维护2个线段。然后暴力模拟一下,由于点数非常多但须要用到的线段树仅仅有3条,所以类似滚动数组的思想优化内存。

    #include<stdio.h>
    #include<iostream>
    #include<string.h>
    #include<algorithm>
    #include<vector>
    #include<set>
    using namespace std;
    #define N 10010
    #define L(x) (x<<1)
    #define R(x) (x<<1|1)
    #define ll int
    int maxn;
    struct hehe{
    	int c[100505];
    	void init(){memset(c, 0, sizeof c);}
    	inline int Lowbit(int x){return x&(-x);}  
    	void change(int i, int x)//i点增量为x  
    	{  
    		while(i <= maxn)  
    		{  
    			c[i] += x;  
    			i += Lowbit(i);  
    		}  
    	}  
    	int sum(int x){//区间求和 [1,x]  
    		int ans = 0;  
    		for(int i = x; i >= 1; i -= Lowbit(i))  
    			ans += c[i];  
    		return ans;  
    	}  
    }tree[2];
    int ans;
    vector<int>l,r,o;
    void work(){
    	if(o.size()<=1)return;
    	tree[0].init(); tree[1].init();
    	for(int i = 0; i < l.size(); i++)
    		tree[0].change(l[i],1);
    	for(int i = 0; i < r.size(); i++)
    		tree[1].change(r[i],1);
    	
    	int L = o[0];
    	for(int i = 1; i < o.size(); i++){
    		int R = o[i];
    		if(L+1<=R-1){
    			int Z = tree[0].sum(R-1)-tree[0].sum(L);
    			int Y = tree[1].sum(R-1)-tree[1].sum(L);
    			ans += (Z!=Y);
    		}
    		L = R;
    	}
    }
    vector<int>a,tmp1, red, tmp2, tmpend;
    void Red(){
    	red.clear();
    	int HHH,EEE; scanf("%d",&HHH);
    	while(HHH--){scanf("%d",&EEE);red.push_back(EEE);}
    	sort(red.begin(),red.end());
    }
    int n;
    int main(){
    	int i,j,num;
    	maxn = 100010;
    	while(~scanf("%d",&n)){
    		ans = 0;
    		l.clear(); r.clear(); tmp1.clear(); a.clear();
    		tmp2.clear(); tmpend.clear();
    		Red();
    		l = tmp1 = red;
    		Red();
    		tmp2 = o = red;
    		for(i = 3; i <= n; i++){
    			Red();
    			r = red;
    			if(i==n)tmpend = red;
    			work();
    			l = o;
    			o = r;
    		}
    		r = tmp1;
    		work();
    
    		l = tmpend;
    		o = tmp1;
    		r = tmp2;
    		work();
    		cout<<ans<<endl;
    	}
    	return 0;
    }
    /*
    3
    2 1 3
    3 1 3 2
    3 1 3 2
    
    
    
    ans:
    0
    2
    
    
    
    
    
    */
    /*
    ll n,m,k;
    ll a[N];
    ll gcd(ll x,ll y){
    if(x>y)swap(x,y);
    while(x){
    y%=x;
    swap(x,y);
    }
    return y;
    }
    int main(){
    ll i, j, u, v, que;
    while(cin>>n>>m>>k){
    for(i = 1; i <= n; i++)cin>>a[i];
    ll _gcd = a[1];
    for(i = 2; i <= n; i++)_gcd = gcd(_gcd,a[i]);
    for(i = 1; i <= n; i++)a[i]/=_gcd;
    
    
    }
    return 0;
    }
    /*
    
    */


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  • 原文地址:https://www.cnblogs.com/yutingliuyl/p/6845743.html
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