LOJ P10117 简单题 题解

每日一题 day15 打卡

Analysis

树状数组

用树状数组来维护每个字符变化的次数，如果是偶数就是0，奇数就是1

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define int long long
#define maxn 100000+10
using namespace std;
inline int read()
{
    int x=0;
    bool f=1;
    char c=getchar();
    for(; !isdigit(c); c=getchar()) if(c=='-') f=0;
    for(; isdigit(c); c=getchar()) x=(x<<3)+(x<<1)+c-'0';
    if(f) return x;
    return 0-x;
}
inline void write(int x)
{
    if(x<0){putchar('-');x=-x;}
    if(x>9)write(x/10);
    putchar(x%10+'0');
}
int n,m;
int tree[maxn];
inline int lowbit(int num)
{
	return num&-num;
}
inline void build(int s,int num)
{
	for(int i=s;i<=n;i+=lowbit(i)) tree[i]+=num;
}
inline int ask(int s)
{
	int ans=0;
	for(int i=s;i>=1;i-=lowbit(i)) ans+=tree[i];
	return ans;
}
signed main()
{
	n=read();m=read();
	for(int i=1;i<=m;i++)
	{
		int in=read();
/*
		for(int i=1;i<=n;i++)
		{
			int tim=ask(i);
			if(tim==0) write(0);
			else if(tim%2==0) write(0);
			else if(tim%2==1) write(1);
			cout<<" ";
		}
		cout<<endl;
*/
		if(in==1)
		{
			int l=read(),r=read();
			build(l,1);
			build(r+1,-1);
		}
		if(in==2)
		{
			int x=read();
			int tim=ask(x);
			if(tim%2==0) write(0);
			else if(tim%2==1) write(1);
			printf("\n");
		}
	}
	return 0;
}

请各位大佬斧正（反正我不认识斧正是什么意思）