【图论07】线段树 1001 敌兵布阵

第一次提交的时候TLE，最后改成C输入输出成功AC，耗时156ms。

通过尝试用不同格式的代码提交之后，发现一个问题，性能影响：输出 > 输入 > 字符串比较（这里更多的是char* 和 string的性能差异）。所以在细节上进行性能优化的时候，应该优先考虑输出、输入。

算法思路：(两种方法)

<1>考察树状数组，区间信息的维护和查询方法。

<2>线段树

树状数组代码： 

//模板开始
#include <string>   
#include <vector>   
#include <algorithm>   
#include <iostream>   
#include <sstream>   
#include <fstream>   
#include <map>   
#include <set>   
#include <cstdio>   
#include <cmath>   
#include <cstdlib>   
#include <ctime>
#include<iomanip>
#include<string.h>
#define SZ(x) (int(x.size()))
using namespace std;

int toInt(string s){
	istringstream sin(s); 
	int t; 
	sin>>t; 
	return t;
}
template<class T> string toString(T x){
	ostringstream sout; 
	sout<<x; 
	return sout.str();
}
typedef long long int64;
int64 toInt64(string s){
	istringstream sin(s); 
	int64 t; 
	sin>>t;
	return t;
}
template<class T> T gcd(T a, T b){ 
	if(a<0) 
		return gcd(-a, b);
	if(b<0) 
		return gcd(a, -b);
	return (b == 0)? a : gcd(b, a % b);
}

#define ifs cin
//模板结束（通用部分）

#define N 50005
int C[N];
int A[N];

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, int n)
{
	while(x <= n)
	{
		C[x] += d;
		x += lowbit(x);
	}
}

void sub(int x, int d, int n)
{
	while(x <= n)
	{
		C[x] -= d;
		x += lowbit(x);
	}
}

//hdoj 1166 敌兵布阵
int main()
{
	//ifstream ifs("shuju.txt", ios::in);
	int n;
	int m;
	int data;
	int op1, op2;
	char s1[10];
	//ifs>>m;
	scanf("%d", &m);
	for(int i = 0; i < m; i++)
	{
		//cout<<"Case "<<i + 1<<":"<<endl;
		printf("Case %d:\n", i + 1);
		//ifs>>n;
		scanf("%d", &n);
		memset(C, 0, sizeof(C));
		memset(A, 0, sizeof(A));
		for(int j = 1; j <= n; j++)
		{
			//ifs>>data;
			scanf("%d", &data);
			A[j] = data;
			add(j, data, n);
		}
		while(scanf("%s", s1))
		{
			if(s1[0] == 'E')
			{
				break;
			}
			//ifs>>op1>>op2;
			scanf("%d%d", &op1, &op2);
			if(s1[0] == 'Q')
			{
				//cout<<sum(op2) - sum(op1 - 1)<<endl;
				printf("%d\n", sum(op2) - sum(op1 - 1));
			}
			else if(s1[0] == 'A')
			{
				A[op1] += op2;
				add(op1, op2, n);
			}
			else if(s1[0] == 'S')
			{
				A[op1] -= op2;
				sub(op1, op2, n);
			}
		}
	}

	return 0;
}

 

线段树代码：

//模板开始
#include <string>   
#include <vector>   
#include <algorithm>   
#include <iostream>   
#include <sstream>   
#include <fstream>   
#include <map>   
#include <set>   
#include <cstdio>   
#include <cmath>   
#include <cstdlib>   
#include <ctime>
#include <iomanip>
#include <queue>
#include <string.h>
#define SZ(x) (int(x.size()))
using namespace std;

int toInt(string s){
	istringstream sin(s); 
	int t; 
	sin>>t; 
	return t;
}
template<class T> string toString(T x){
	ostringstream sout; 
	sout<<x; 
	return sout.str();
}
typedef long long int64;
int64 toInt64(string s){
	istringstream sin(s); 
	int64 t; 
	sin>>t;
	return t;
}
template<class T> T gcd(T a, T b){ 
	if(a<0) 
		return gcd(-a, b);
	if(b<0) 
		return gcd(a, -b);
	return (b == 0)? a : gcd(b, a % b);
}

#define LOCAL
//模板结束（通用部分）

#define MAXN 2000200

int sum[MAXN];
int ql, qr;
int p, v;
int N;
int zhishu;

int query(int o, int L, int R)
{
	int M = L + (R - L) / 2, ans = 0;
	if(ql <= L && R <= qr)
	{
		return sum[o];
	}
	if(ql <= M)
	{
		ans += query(o * 2, L, M);
	}
	if(M < qr)
	{
		ans += query(o * 2 + 1, M + 1, R);
	}
	return ans;
}

void update1(int o, int L, int R)
{
	int M = L + (R - L) / 2;
	if(L == R)
	{
		sum[o] += v;
	}
	else
	{
		if(p <= M)
		{
			update1(o * 2, L, M);
		}
		else
		{
			update1(o * 2 + 1, M + 1, R);
		}
		sum[o] = sum[o * 2] + sum[o * 2 + 1]; 
	}
}

void update2(int o, int L, int R)
{
	int M = L + (R - L) / 2;
	if(L == R)
	{
		sum[o] -= v;
	}
	else
	{
		if(p <= M)
		{
			update2(o * 2, L, M);
		}
		else
		{
			update2(o * 2 + 1, M + 1, R);
		}
		sum[o] = sum[o * 2] + sum[o * 2 + 1]; 
	}
}

void init()
{
	zhishu = 0;
	//cin>>N;
	scanf("%d", &N);
	while((1<<zhishu) < N)
	{
		zhishu++;
	}
	int up_max = (1<<(zhishu + 1)) - 1;
	int chuzhi = 1<<(zhishu);
	for(int i = chuzhi; i <= chuzhi + N - 1; i++)
	{
		//cin>>sum[i];
		scanf("%d", &sum[i]);
	}
	for(int i = chuzhi + N; i <= up_max; i++)
	{
		sum[i] = 0;
	}
	for(int i = (1<<zhishu) - 1; i >= 1; i--)
	{
		sum[i] = sum[i * 2] + sum[i * 2 + 1];
	}
}

int main()
{
#ifdef LOCAL
	//freopen("shuju.txt", "r", stdin);
#endif

	char a[10];
	int b, c;
	int T;
	//cin>>T;
	scanf("%d", &T);
	for(int tt = 1; tt <= T; tt++)
	{
		cout<<"Case "<<tt<<":"<<endl;
		init();		
		while(scanf("%s", a) == 1 && strcmp(a, "End") != 0)
		{
			//cin>>b>>c;
			scanf("%d%d", &b, &c);
			if(!strcmp(a, "Query"))
			{
				ql = b;
				qr = c;
				cout<<query(1, 1, 1<<zhishu)<<endl;
			}
			if(!strcmp(a, "Add"))
			{
				p = b;
				v = c;
				update1(1, 1, 1<<zhishu);
			}
			if(!strcmp(a, "Sub"))
			{
				p = b;
				v = c;
				update2(1, 1, 1<<zhishu);
			}
		}
	}

	return 0;
}