牛客練習賽D二分（差分）

思路：吧每個詢問轉化爲區間，然後差分查詢區間最大重合。

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <set>
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define space putchar(' ')
#define enter putchar('\n')
typedef pair<int ,int> PII;
const int mod=1e4+7;
const int N=1e5+10;
const int inf=0x7f7f7f7f;


  ll gcd(ll a,ll b){ return b==0?a:gcd(b,a%b); }

ll lcm(ll a,ll b)
{
    return a*(b/gcd(a,b));
}

template <class T>
void read(T &x){
    char c;
    bool op = 0;
    while(c = getchar(), c < '0' || c > '9')
	if(c == '-') op = 1;
    x = c - '0';
    while(c = getchar(), c >= '0' && c <= '9')
	x = x * 10 + c - '0';
    if(op) x = -x;
}
template <class T>
void write(T x){
    if(x < 0) x = -x, putchar('-');
    if(x >= 10) write(x / 10);
    putchar('0' + x % 10);
}
ll ksm(ll a,ll k,ll p)
{
    ll res=1;
    while(k)
    {
        if(k&1)res=res*a%p;
        a=a*a%p;
        k>>=1;
    }
    return res;
}
map<int,int> mp;
int main()
{
 int n;
 read(n);

 for(int i=1;i<=n;i++)
 {
    int x;char y;
    cin>>x>>y;
    if(y=='.')mp[x]++,mp[x+1]--;
    else if(y=='+')mp[-inf]++,mp[x]--;
    else mp[x+1]++,mp[inf]--;
 }
 int ans=-inf,sum=0;
 for(auto x:mp)
 {
     sum+=x.second;
     ans=max(ans,sum);
 }
 write(ans);



    return 0;
}