HDU - 1166 - 敌兵布阵（ 树状数组 ）

题目链接：点击进入

题目

思路

树状数组实现 -> 单点修改 + 区间查询
（ 这题线段树也可以写，不过树状数组码量要小 ）

代码

// Problem: 敌兵布阵
// Contest: Virtual Judge - HDU
// URL: https://vjudge.net/problem/HDU-1166
// Memory Limit: 32 MB
// Time Limit: 1000 ms
// 
// Powered by CP Editor (https://cpeditor.org)

//#pragma GCC optimize(3)//O3
//#pragma GCC optimize(2)//O2
#include<iostream>
#include<string>
#include<map>
#include<set>
//#include<unordered_map>
#include<queue>
#include<cstdio>
#include<vector>
#include<cstring>
#include<stack>
#include<algorithm>
#include<iomanip>
#include<cmath>
#include<fstream>
#define X first
#define Y second
#define best 131 
#define INF 0x3f3f3f3f3f3f3f3f
#define pii pair<int,int>
#define lowbit(x) x & -x
#define inf 0x3f3f3f3f
//#define int long long
//#define double long double
//#define rep(i,x,y) for(register int i = x; i <= y;++i)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const double pai=acos(-1.0);
const int maxn=1e6+10;
const int mod=998244353;
const double eps=1e-9;
const int N=5e3+10;
/*--------------------------------------------*/
inline int read()
{
    int k = 0, f = 1 ;
    char c = getchar() ;
    while(!isdigit(c)){if(c == '-') f = -1 ;c = getchar() ;}
    while(isdigit(c)) k = (k << 1) + (k << 3) + c - 48 ,c = getchar() ;
    return k * f ;
}
/*--------------------------------------------*/

int t,n,a[maxn],c[maxn],tot;
void add(int x,int val)
{
	for(int i=x;i<=n;i+=lowbit(i))
		c[i]+=val;
}
int getsum(int x)
{
	int sum=0;
	for(int i=x;i>=1;i-=lowbit(i))
		sum+=c[i];
	return sum;
}
int main() 
{
	ios::sync_with_stdio(false);
	cin.tie(0);cout.tie(0);
	cin>>t;
	while(t--)
	{
		cin>>n;
		for(int i=1;i<=n;i++)
		{
			cin>>a[i];
			add(i,a[i]);
		}
		string s;
		cout<<"Case "<<++tot<<":"<<endl;
		while(cin>>s)
		{
			if(s=="End") break;
			int x,y;
			cin>>x>>y;
			if(s[0]=='Q')
				cout<<getsum(y)-getsum(x-1)<<endl;
			else if(s[0]=='S')
				add(x,-y);
			else if(s[0]=='A')
				add(x,y);
		}
		for(int i=1;i<=n;i++) c[i]=0;
	}
    return 0;
}