hdu 1166 敌兵布阵

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1166；

树状数组：

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;

const int maxn = 50050;
int n,T;
int a[maxn];
int C[maxn];
int lowbit(int x){
    return x&(-x);
}
int sum(int x){
    int ret = 0;
    while(x > 0){
        ret += C[x];
        x -= lowbit(x);
    }
    return ret;
}
void add(int x,int d){
    while(x<=n){
        C[x] += d;
        x += lowbit(x);
    }
} 
int main()
{
    //if(freopen("input.txt","r",stdin)== NULL)  {printf("Error\n"); exit(0);}
    cin>>T;
    char ch[10];
    for(int t=1;t<=T;t++){
        cin>>n;
        for(int i=1;i<=n;i++) scanf("%d",&a[i]);
        memset(C,0,sizeof(C));
        for(int i=1;i<=n;i++){
            for(int j=i-lowbit(i)+1;j<=i;j++){
                C[i] += a[j];
            }
        }
        printf("Case %d:\n",t);
        scanf("%s",ch);    
        while(strcmp(ch,"End")){
            if(!strcmp(ch,"Query")){
                int a,b;
                   scanf("%d%d",&a,&b);
                   int ans = sum(b) - sum(a-1);
                   printf("%d\n",ans);
            }
            else if(!strcmp(ch,"Add")){
                int a,b; 
                scanf("%d%d",&a,&b);
                add(a,b);
            }
            else if(!strcmp(ch,"Sub")){
                int a,b;
                scanf("%d%d",&a,&b);
                add(a,-b);
            }
            scanf("%s",ch);    
        } 
    }
    
}

线段树：

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
const int maxn = 50050;

int tree[4*maxn];
int a[maxn];
int n,T;
char ch[10];

void build(int u,int l,int r){
    if(l == r){
        tree[u] = a[l];
        return;
    }
    int mid = (l + r)>>1; 
    build(2*u,l,mid);
    build(2*u+1,mid+1,r); 
    tree[u] = tree[2*u] + tree[2*u+1];
}
void update(int u,int l,int r,int goal,int num){
    if(l == r){
        tree[u] += num;
        return;
    }
    int mid = (l+r)/2;                      //printf("%d %d %d\n",l,r,mid);
    if(goal <= mid)     update(2*u,l,mid,goal,num);
    else                update(2*u+1,mid+1,r,goal,num);
    tree[u] = tree[2*u] + tree[2*u+1];  //printf("tree %d %d         %d %d         %d\n",u,tree[u] ,2*u,tree[2*u] ,tree[2*u+1]);
}
int query(int u,int l,int r,int tl,int tr){
    if(tl<=l && r<=tr){
        return tree[u];
    }
    int mid = (l + r)/2;
    if(tr <= mid)       return query(2*u,l,mid,tl,tr);  
    else if(tl > mid)   return query(2*u+1,mid+1,r,tl,tr);
    else                 return query(2*u,l,mid,tl,tr)+query(2*u+1,mid+1,r,tl,tr);
    
}
int main()
{
    //if(freopen("input.txt","r",stdin)== NULL)  {printf("Error\n"); exit(0);}
    cin>>T;
    for(int t=1;t<=T;t++){
        cin>>n;
        memset(tree,0,sizeof(tree));
        for(int i=1;i<=n;i++) cin>>a[i];  
        
        int tl,tr;
        build(1,1,n);
        printf("Case %d:\n",t);
        cin>>ch;
        while(strcmp(ch,"End")){
            if(!strcmp(ch,"Query")){
                   scanf("%d%d",&tl,&tr);
                   int ans = query(1,1,n,tl,tr);
                   printf("%d\n",ans);
            }
            else if(!strcmp(ch,"Add")){
                int a,b; 
                scanf("%d%d",&a,&b);
                update(1,1,n,a,b);
            }
            else if(!strcmp(ch,"Sub")){
                int a,b;
                scanf("%d%d",&a,&b);
                update(1,1,n,a,-b);
            }
           scanf("%s",ch);    
        }
    }
    return 0;
}