HDU - 1166 敌兵布阵（线段树）

https://cn.vjudge.net/problem/HDU-1166

中文题目，没啥好说，线段树的点修改和区间查询。用树状数组做也是ok的

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <algorithm>
#include <cmath>
#include <ctime>
#include <vector>
#include <queue>
#include <map>
#include <stack>
#include <set>
#include <bitset>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define ms(a, b) memset(a, b, sizeof(a))
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define eps 0.0000000001
#define IOS ios::sync_with_stdio(0);cin.tie(0);
#define random(a, b) rand()*rand()%(b-a+1)+a
#define pi acos(-1)
const ll INF = 0x3f3f3f3f3f3f3f3fll;
const int inf = 0x3f3f3f3f;
const int maxn = 50000 + 10;
const int maxm = 200000 + 10;
const int mod = 998244353;
int n;
struct ND{
    int l,r;
    int sum;
}tree[maxn<<2];
int a[maxn];
void pushup(int rt){
    tree[rt].sum=tree[rt<<1].sum+tree[rt<<1|1].sum;
}
void build(int rt,int l,int r){
    tree[rt].l=l,tree[rt].r=r;
    if(l==r){
        tree[rt].sum=a[l];
        return;
    }
    int mid=(l+r)>>1;
    build(rt<<1,l,mid);
    build(rt<<1|1,mid+1,r);
    pushup(rt);
}
void update(int rt,int pos,int val){
    if(tree[rt].l==tree[rt].r){
        tree[rt].sum+=val;
        return;
    }
    int mid=(tree[rt].l+tree[rt].r)>>1;
    if(mid>=pos) update(rt<<1,pos,val);
    else update(rt<<1|1,pos,val);
    pushup(rt);
}
int query(int rt,int L,int R){
    if(L<=tree[rt].l&&tree[rt].r<=R) return tree[rt].sum;
    int sum=0;
    int mid=(tree[rt].l+tree[rt].r)>>1;
    if(mid<R) sum+=query(rt<<1|1,L,R);
    if(mid>=L) sum+=query(rt<<1,L,R);
    return sum;
}
int main() {
#ifdef LOCAL
    freopen("in.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);
#endif
    int t;
    int cas=1;
    scanf("%d",&t);
    while(t--){
        printf("Case %d:\n",cas++);
        scanf("%d",&n);
        for(int i=1;i<=n;i++) scanf("%d",&a[i]);
        build(1,1,n);
        char op[10];
        int x,y;
        while(scanf("%s",op)==1){
            if(op[0]=='E') break;
            if(op[0]=='A'){
                scanf("%d%d",&x,&y);
                update(1,x,y);
            }else if(op[0]=='S'){
                scanf("%d%d",&x,&y);
                update(1,x,-y);
            }else{
                scanf("%d%d",&x,&y);
                printf("%d\n",query(1,x,y));
            }
        }
    }
    return 0;
}