A - 敌兵布阵（HDU 1166）

A - 敌兵布阵

HDU - 1166

思路：线段树单点修改+区间查询。

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define MAXN 50001
using namespace std;
string s;
int t,n,tot;
struct nond{
    int l,r,sum;
}tree[MAXN*4];
void up(int now){
    tree[now].sum=tree[now*2].sum+tree[now*2+1].sum;
}
void build(int now,int l,int r){
    tree[now].l=l;tree[now].r=r;
    if(tree[now].l==tree[now].r){
        scanf("%d",&tree[now].sum);
        return ;
    }
    int mid=(tree[now].l+tree[now].r)/2;
    build(now*2,l,mid);
    build(now*2+1,mid+1,r);
    up(now);
}
void change(int now,int x,int k){
    if(tree[now].l==tree[now].r){
        tree[now].sum+=k;
        return ;
    }
    int mid=(tree[now].l+tree[now].r)/2;
    if(x<=mid)    change(now*2,x,k);
    else change(now*2+1,x,k);
    up(now);
}
int query(int now,int l,int r){
    if(tree[now].l==l&&tree[now].r==r)
        return tree[now].sum;
    int mid=(tree[now].l+tree[now].r)/2;
    if(r<=mid)    return query(now*2,l,r);
    else if(l>mid)    return query(now*2+1,l,r);
    else    return query(now*2,l,mid)+query(now*2+1,mid+1,r);
}
int main(){
    scanf("%d",&t);
    while(t--){
        tot++;printf("Case %d:\n",tot);
        scanf("%d",&n);
        build(1,1,n);
        int x,y;
        while(cin>>s&&s[0]!=‘E‘){
            if(s[0]==‘Q‘){ scanf("%d%d",&x,&y);printf("%d\n",query(1,x,y)); }
            else if(s[0]==‘A‘){ scanf("%d%d",&x,&y);change(1,x,y); }
            else if(s[0]==‘S‘){ scanf("%d%d",&x,&y);change(1,x,-y); }
        }
    }
}

原文地址：https://www.cnblogs.com/cangT-Tlan/p/8463991.html