HDU1166 敌兵布阵

简单线段树，单点更新，区间查询，自下向上更新结点的信息~

#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int maxn=1e6+14;
struct node {
    int l;
    int r;
    int sum;
}segTree[maxn*3];
int num[maxn];
void build (int i,int l,int r) {
    segTree[i].l=l;
    segTree[i].r=r;
    if (l==r) {
        segTree[i].sum=num[l];
        return;
    }
    int mid=(l+r)>>1;
    build (i<<1,l,mid);
    build (i<<1|1,mid+1,r);
    segTree[i].sum=segTree[i<<1].sum+segTree[i<<1|1].sum; 
} 
void add (int i,int t,int b) {
    segTree[i].sum+=b;
    if (segTree[i].l==t&&segTree[i].r==t) return;
    int mid=(segTree[i].l+segTree[i].r)>>1;
    if (t<=mid) add (i<<1,t,b);
    else add (i<<1|1,t,b); 
}
int query (int i,int l,int r) {
    if (l==segTree[i].l&&r==segTree[i].r) return segTree[i].sum;
    int mid=(segTree[i].l+segTree[i].r)>>1;
    if (r<=mid) return query(i<<1,l,r);
    else if (l>mid) return query(i<<1|1,l,r);
    else return query(i<<1,l,mid)+query(i<<1|1,mid+1,r);
}
int main () {
    int T;
    int ans=0;
    int n;
    int a,b;
    char s[maxn];
    scanf ("%d",&T);
    while (T--) {
        ans++;
        scanf ("%d",&n);
        for (int i=1;i<=n;i++) scanf ("%d",&num[i]);
        build (1,1,n);
        printf ("Case %d:\n",ans);
        while (scanf("%s",s)) {
            if (strcmp(s,"End")==0) break;
            scanf ("%d %d",&a,&b);
            if (strcmp(s,"Add")==0) add(1,a,b);
            else if (strcmp(s,"Sub")==0) add(1,a,-b);
            else printf ("%d\n",query(1,a,b));
        } 
    }
    return 0;
}