hdu(1166)——敌兵布阵(更新节点，区间求和）

来源：互联网发布：广联达电力预算软件编辑：程序博客网时间：2024/06/04 01:23

这是一道最简单的线段树的更新节点与区间查询。

当然practic makes perfect~ 现在我已经能够比较熟练地打出来了。

但是还有一些细节要注意就是对于父节点的更新。

#include<stdio.h>#include<string.h>#include<algorithm>#include<iostream>using namespace std;#define maxn 55555char a[55];struct node{    int l,r,sum;    int add;}tree[maxn*4];int ans=0;void pushup(int v){    int temp=v*2;    tree[v].sum=tree[temp].sum+tree[temp+1].sum;}void pushdown(int v){    int temp=v*2;    tree[temp].add+=tree[v].add;    tree[temp+1].add+=tree[v].add;    tree[temp].sum+=tree[v].add*(tree[temp].r-tree[temp].l+1);    tree[temp+1].sum+=tree[v].add*(tree[temp+1].r-tree[temp+1].l+1);    tree[v].add=0;}void build(int l,int r,int v){    tree[v].l=l;     tree[v].r=r;    tree[v].add=0;    if(l==r){        scanf("%d",&tree[v].sum);        return;    }    int temp=v*2;    int mid=(tree[v].l+tree[v].r)/2;    build(l,mid,temp);    build(mid+1,r,temp+1);    pushup(v);}void update(int pos,int v,int x){    if(pos==tree[v].l&&tree[v].r==pos){        tree[v].add+=x;        tree[v].sum+=x*(tree[v].r-tree[v].l+1);        return ;    }    if(tree[v].add) pushdown(v);    int mid=(tree[v].l+tree[v].r)/2;    int temp=v*2;    if(pos<=mid) update(pos,temp,x);    else update(pos,temp+1,x);    pushup(v);            //!!!}void query(int l,int r,int v){    if(r<tree[v].l||tree[v].r<l) return;    if(l<=tree[v].l&&tree[v].r<=r){        ans+=tree[v].sum;        return;    }    if(tree[v].add) pushdown(v);    int mid=(tree[v].l+tree[v].r)/2;    int temp=v*2;    if(r<=mid) query(l,r,temp);    else if(mid<l) query(l,r,temp+1);    else{        query(l,mid,temp);        query(mid+1,r,temp+1);    }}int main(){    int T,n;    int j=1;    scanf("%d",&T);    while(T--){        scanf("%d",&n);        ans=0;        bool ff=false;        build(1,n,1);        #if 1        while(1){            scanf("%s",a);            if(strcmp(a,"End")==0) break;            if(strcmp(a,"Add")==0){                int r,s;                scanf("%d%d",&r,&s);                update(r,1,s);            }            if(strcmp(a,"Sub")==0){                int r,s;                scanf("%d%d",&r,&s);                update(r,1,-s);            }            if(strcmp(a,"Query")==0){                ans=0;                int r,s;                scanf("%d%d",&r,&s);                query(r,s,1);                if(!ff) printf("Case %d:\n",j++),ff=true;                printf("%d\n",ans);            }        }        #endif    }}

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