Count the Colors ZOJ

GO

题意：给一个区间，有n次染色操作，每次将[x1, x2]染为c，求最后每种颜色各有多少线段可以看到。

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<cstdlib>
#include<queue>
#include<set>
#include<vector>

using namespace std;
#define INF 0x3f3f3f3f
#define eps 1e-10
typedef long long LL;
const int MAXN = 1e5+5;
const int mod = 998244353;

LL st[MAXN << 2];
int vis[MAXN];
void pushdown(int o)
{
    if(st[o] != -1)
    {
        st[o << 1] = st[o];
        st[o << 1 | 1] = st[o];
        st[o] = -1;
        return;
    }
}
void update(int o,int l,int r,int ql,int qr,int c)
{
    if(ql <= l && r <= qr) {
        st[o] = c;
        return;
    }
    else {
        if(st[o] != c){
            pushdown(o);
            int m = (l + r) >> 1;
            if(ql <= m) update(o << 1,l,m,ql,qr,c);
            if(m + 1 <= qr) update(o << 1 | 1,m + 1,r,ql,qr,c);
        }
        else return;
    }

}
int last;
void query(int o,int l,int r)
{
    if(l == r)
    {
        if(st[o] != -1 && st[o] != last)
            vis[st[o]]++;
        last = st[o];
        return;
    }
    pushdown(o);
    int m = (l + r) >> 1;
    query(o << 1,l,m);
    query(o << 1 | 1,m + 1,r);
}
int main()
{
    int n;
    while(~scanf("%d",&n))
    {
        memset(st,-1,sizeof st);
        while(n--)
        {
            int x,y,c;
            scanf("%d %d %d",&x,&y,&c);
            update(1,1,8000,x + 1,y,c);
        }
        memset(vis,0,sizeof vis);
        last = -1;
        query(1,1,8000);
        for(int i = 0; i <= 8000; i++)
            if(vis[i])
                printf("%d %d
",i,vis[i]);
        printf("
");
    }
}