ZOJ 1610 Count the Colors

最新推荐文章于 2022-02-25 19:38:17 发布

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文章标签：

#colors #tree #insert #query #c #struct

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本文介绍了一种使用线段树解决区间染色问题的方法，通过递归更新和查询来统计不同颜色出现的次数及长度。代码示例中包含了两种实现方式：数组形式和指针形式。

//线段树涂色问题: 对每一段区间进行染色 统计出现的颜色和该颜色的长度
//这里建图时 以线段长度1为单位节点

#include <iostream>
#include <cstdio>
using namespace std;

const int N = 20001;
int temp;

struct Node
{
	int L;
	int R;
	int kind;
};
Node segtree[N];

int color[8001];

void create_tree( int n, int l, int r )
{                    
	segtree[n].L = l;
	segtree[n].R = r;
	segtree[n].kind = -1;

	if( l + 1 == r ) return;

	int mid = ( l + r ) >> 1;
	create_tree( n * 2, l, mid );
	create_tree( n * 2 + 1, mid, r );
}

void insert_tree( int n, int l, int r, int c) 
{             
	if( l == r ) return;
	
	if( segtree[n].kind == c ) return;			//颜色相同，返回 

	if( l == segtree[n].L && segtree[n].R == r ) 
	{                
		segtree[n].kind = c;
		return;
	}
	
	if( segtree[n].kind >= 0 ) //存在颜色，做更新
	{                        
		segtree[ n * 2 ].kind = segtree[n].kind;
		segtree[ n * 2 + 1 ].kind = segtree[n].kind;
		segtree[n].kind = -2;       //传值下去，完成该整段区间更新后赋值-2
	}
	
	int mid = ( segtree[n].L + segtree[n].R ) >> 1;
	
	if( r <= mid ) 
	{
		insert_tree( n * 2, l, r, c );
	}
	else if( l >= mid ) 
	{
		insert_tree( n * 2 + 1, l, r, c );
	}
	else 
	{
		insert_tree( n * 2, l, mid, c);
		insert_tree( n * 2 + 1, mid, r, c );
	}
}

void count( int n ) //先序遍历
{                                      
	if( segtree[n].kind != -1 && segtree[n].kind != -2 )  //颜色不为-1和-2 
	{          
		if( segtree[n].kind != temp ) 
		{
			color[ segtree[n].kind ]++;
			temp = segtree[n].kind;
		}
		return;
	}
	
	if( segtree[n].L + 1 != segtree[n].R ) //非子节点
	{                 
		count( n * 2 );
		count( n * 2 + 1 );
	}
	
	else temp = -1;
	
}

int main() 
{
	int i, t;
	while( scanf("%d", &t) != EOF ) 
	{
		create_tree( 1, 0, 8000 );

		for(i=0;i<t;i++)
		{
			int a,b,c;

			scanf("%d%d%d", &a, &b, &c);

			insert_tree(1, a, b, c);
		}
		temp = -1;

		fill(color,color+8001,0);

		count(1);

		for( i = 0; i <= 8000; i++ ) 
		{
			if( color[i] ) printf("%d %d\n", i, color[i]);
		}
		printf("\n");
		
	}
	return 0;
}

//线段树指针形式 
//注释的代码 WA 未解

#include<iostream>
#include<cstdio>
using namespace std;

const int MaxN=8002;

struct Cnode
{
    int L,R;      
    Cnode *pLeft,*pRight; 
	
    int col; 
};

Cnode Tree[MaxN*2];    

int Ans[MaxN];
int Col[MaxN];

int nCount=0; 

int m;
int temp;


void BuildTree(Cnode *pRoot,int L,int R) //Notice ---> 每个节点代表一个区间
{
    pRoot->L=L;
    pRoot->R=R;
    pRoot->col=-1;
	
    if(L+1==R) 
	{
		pRoot->pLeft=NULL;
		pRoot->pRight=NULL;
		return;
	}
	
	nCount++;
	pRoot->pLeft = Tree + nCount;
	nCount++;
	pRoot->pRight = Tree + nCount;
	
	BuildTree( pRoot->pLeft, L, ( L + R )/2);
	BuildTree( pRoot->pRight, (L + R) / 2, R);
}

int Mid( Cnode * pRoot)
{
    return (pRoot->L + pRoot->R)/2;
}

void update(Cnode *pRoot,int a,int b,int c)
{	
	if(pRoot->col == c) return; //同色不处理
	
    if(pRoot->L==a && pRoot->R==b) //完全覆盖才涂色 
    {
        pRoot->col=c;
        return ;
    }
	
    if(pRoot->col>=0)
    {
        pRoot->pLeft->col = pRoot->pRight->col = pRoot->col;
        pRoot->col=-2;
    }
	
    if(b<=Mid(pRoot)) update(pRoot->pLeft,a,b,c);
	
    else if(a>= (Mid(pRoot)) ) update(pRoot->pRight,a,b,c);
	
    else 
    {
        update(pRoot->pLeft, a, Mid(pRoot), c);
        update(pRoot->pRight, Mid(pRoot), b, c);
    }
}

/*void Query(Cnode *pRoot,int a,int b)
{
	if(pRoot == NULL) return;

    if(pRoot->col!=-1 && pRoot->col!=-2)
    {
        for(int i=pRoot->L; i<=pRoot->R; i++) 
		{
			Col[i]=pRoot->col;
		}
		return;
    }

    if(b<= Mid(pRoot) ) 
		
        Query(pRoot->pLeft,a,b);
	
    else if(a >=(Mid(pRoot)) ) 
		
        Query(pRoot->pRight,a,b);
	
    else 
    {
		Query(pRoot->pLeft, a, Mid(pRoot));
		Query(pRoot->pRight, Mid(pRoot), b);
    }
}*/

void count( Cnode *pRoot ) //先序遍历
{  
	if( pRoot->col != -1 && pRoot->col != -2 )  //颜色不为-1和-2 
	{          
		if( pRoot->col != temp ) 
		{
			Ans[ pRoot->col ]++;
			temp = pRoot->col;
		}
		return;
	}
	
	if( pRoot->L + 1 != pRoot->R ) //非子节点
	{                 
		count( pRoot->pLeft );
		count( pRoot->pRight );
	}
	
	else temp = -1;
	
}

void run()
{
    int i;
	
    nCount=0;
    BuildTree(Tree,0,MaxN);
	
	fill(Ans,Ans+MaxN,0);
	fill(Col,Col+MaxN,-1);
	
    for(i=0;i<m;i++) 
    {
        int a,b,c;
        scanf("%d%d%d",&a,&b,&c);
        update(Tree,a,b,c);
    }
	
    /*Query(Tree,0,MaxN);
	
	int init=-1;
	
	for(i=0;i<MaxN;i++) if(Col[i]!=-1)
	{
		if(Col[i]!=init)
		{
			Ans[Col[i]]++;
			init=Col[i];
		}
	}*/

	temp = -1;

	count(Tree);
	
	for(i=0;i<MaxN;i++) if(Ans[i])
	{
		printf("%d %d\n",i,Ans[i]);
	}
	printf("\n");
}

int main()
{
	while(scanf("%d",&m)!=EOF) run();
    return 0;
}

Example

0 4 4
0 3 1
3 4 2
0 2 2
0 2 3

-1---->未赋值

-2---->该节点已经结束lazy操作往下跟新