hdu 1698 线段树（成段替换 区间求和）

一条钩子由许多小钩子组成 更新一段小钩子 变成铜银金 价值分别变成1 2 3 输出最后的总价值

Sample Input
1
10
2
1 5 2
5 9 3

Sample Output
Case 1: The total value of the hook is 24.

# include <iostream>
# include <cstdio>
# include <cstring>
# include <algorithm>
# include <cmath>
# include <queue>
# define LL long long
using namespace std ;


const int maxn = 100010;

int sum[maxn<<2] ; //结点开4倍
int col[maxn<<2] ; //延迟标记

void PushUP(int rt) //更新到父节点
{
    sum[rt] = sum[rt * 2] + sum[rt * 2 + 1] ; //rt 为当前结点
}

void PushDown(int rt , int m )  //向下更新
{
    if (col[rt])
    {
        col[rt * 2] = col[rt * 2 + 1] = col[rt] ;
        sum[rt * 2] = (m - m / 2) * col[rt] ;
        sum[rt * 2 + 1] = (m / 2) * col[rt] ;
        col[rt] = 0 ;
    }
}

void build(int l , int r , int rt) //构建线段树
{
    col[rt] = 0 ;
    if (l == r)
    {
        sum[rt] = 1 ;
        return ;
    }
    int m = (l + r) / 2 ;
    build(l , m , rt * 2) ;
    build(m + 1 , r , rt * 2 +1) ;
    PushUP(rt) ;
}

void updata(int L , int R , int c , int l , int r , int rt)
{
    if (L <= l && r <= R)
        {
            col[rt] = c ;
            sum[rt] = (r - l + 1) * c ;
            return  ;
        }
    PushDown(rt , r - l + 1) ;
    int m = (l + r) / 2 ;

    if (L <= m)
       updata(L , R , c , l , m , rt * 2) ;
    if (R > m)
       updata(L , R , c , m + 1 , r , rt * 2 + 1) ;

    PushUP(rt) ;
}



int main ()
{
    //freopen("in.txt","r",stdin) ;
    int n , m ;
    int T ;
    int Case = 0 ;
    scanf("%d" , &T) ;
    while(T--)
    {
        Case++ ;
        scanf("%d%d",&n,&m);
        build(1 , n , 1) ;
        while(m--)
        {
            int a , b , c ;
            scanf("%d%d%d",&a,&b,&c);
            updata(a , b , c , 1 , n , 1) ;
        }
        printf("Case %d: The total value of the hook is %d.
",Case , sum[1]);
    }

    return 0 ;
}