hdu1198 Just a Hook 线段树区间赋值

#include<iostream>
#include<cstdio>
#include<cstring>
#define N 500005
using namespace std;

int n,m,c
[2],sum
,val
;
int read(){
int x=0; char ch=getchar();
while (ch<'0' || ch>'9') ch=getchar();
while (ch>='0' && ch<='9'){ x=x*10+ch-'0'; ch=getchar(); }
return x;
}
void pushdown(int k){
if (val[k]!=-1){
int l=c[k][0],r=c[k][1],mid=(l+r)>>1;
val[k<<1]=val[k<<1|1]=val[k];
sum[k<<1]=val[k]*(mid-l+1); sum[k<<1|1]=val[k]*(r-mid);
val[k]=-1;
}
}
void build(int k,int x,int y){
c[k][0]=x; c[k][1]=y; val[k]=-1;
if (x==y){ sum[k]=1; return; }
int mid=(x+y)>>1; build(k<<1,x,mid); build(k<<1|1,mid+1,y);
sum[k]=sum[k<<1]+sum[k<<1|1];
}
void mdy(int k,int x,int y,int v){
int l=c[k][0],r=c[k][1],mid=(l+r)>>1;
if (x==l && y==r){
val[k]=v; sum[k]=v*(r-l+1); return;
}
pushdown(k);
if (y<=mid) mdy(k<<1,x,y,v); else
if (x>mid) mdy(k<<1|1,x,y,v); else{
mdy(k<<1,x,mid,v); mdy(k<<1|1,mid+1,y,v);
}
sum[k]=sum[k<<1]+sum[k<<1|1];
}
int main(){
int cas=read(),ri;
for (ri=1; ri<=cas; ri++){
n=read(); m=read(); build(1,1,n);
while (m--){
int x=read(),y=read(),z=read();
mdy(1,x,y,z);
}
printf("Case %d: The total value of the hook is %d.\n",ri,sum[1]);
}
return 0;
}