zoj 1610 Count the Colors

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=610

先用线段树维护区间颜色的覆盖，然后在把区间的颜色映射到数组，再从数组统计颜色。

#include <cstdio>
#include <cstring>
#include <algorithm>
#define maxn 100000
using namespace std;

int n;
int min1;
struct node1
{
int x1,x2,c;
}p[maxn];
struct node
{
int l,r;
int cover;
}tree[maxn*4];
int vis[maxn];
int colo[maxn];

void build(int i,int l,int r)
{
tree[i].l=l; tree[i].r=r;
tree[i].cover=-1;
if(l==r) return ;
int mid=(l+r)>>1;
build(i<<1,l,mid);
build(i<<1|1,mid+1,r);
}
void down(int i)
{
if(tree[i].l==tree[i].r) return ;
if(tree[i].cover!=-1)
{
tree[i<<1].cover=tree[i<<1|1].cover=tree[i].cover;
tree[i].cover=-1;
}
}
void update(int i,int l,int r,int col)
{
if(tree[i].l==l&&tree[i].r==r)
{
tree[i].cover=col;
return ;
}
down(i);
int mid=(tree[i].l+tree[i].r)>>1;
if(r<=mid)
{
update(i<<1,l,r,col);
}
else if(l>mid)
{
update(i<<1|1,l,r,col);
}
else
{
update(i<<1,l,mid,col);
update(i<<1|1,mid+1,r,col);
}
}

void search1(int i)
{
if(tree[i].cover!=-1)
{
for(int k=tree[i].l; k<=tree[i].r; k++)
{
vis[k]=tree[i].cover;
}
return ;
}
if(tree[i].l==tree[i].r) return;
search1(i<<1);
search1(i<<1|1);
}

int main()
{
while(scanf("%d",&n)!=EOF)
{
int max1=0,max2=-1;
min1=maxn;
for(int i=1; i<=n; i++)
{
scanf("%d%d%d",&p[i].x1,&p[i].x2,&p[i].c);
max1=max(max1,p[i].x2);
max2=max(max2,p[i].c);
min1=min(min1,p[i].c);
}
build(1,0,max1*2-1);
for(int i=0; i<=max1*2; i++)
{
vis[i]=-1;
}
for(int i=1; i<=n; i++)
{
update(1,p[i].x1*2,p[i].x2*2-1,p[i].c);
}
search1(1);
memset(colo,0,sizeof(colo));
for(int i=0; i<=max1*2; i++)
{
if(vis[i]!=-1)
{
int mm=vis[i];
colo[mm]++;
while(vis[i]==mm&&i<=max1*2) i++;
}
}
for(int i=min1; i<=max2; i++)
{
if(colo[i])
{
printf("%d %d\n",i,colo[i]);
}
}
printf("\n");
}
return 0;
}

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