hdu1198 Just a Hook 线段树区间赋值

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继续补线段树>_<。一句话题意：多组数据，区间赋值修改，最后求总和。线段树lazy tag直接上：

AC代码如下：

#include<iostream>#include<cstdio>#include<cstring>#define N 500005using namespace std;int n,m,c[N][2],sum[N],val[N];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); elseif (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;}

by lych

2016.1.9

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