P4875 改掉WA就行了 T我自行解决

#include<bits/stdc++.h>
using namespace std;
#define hash ___A__
const int N=1e5+5;
int n,m,ans=-1;
struct cow{
    int pos,col;
    friend int operator<(cow x,cow y){
        return x.pos<y.pos;
    }
}a[N];
int count(int x){
    int ret=0;
    while(x){
        ret+=x%2,x/=2;
    }
    return ret;
}
int calc(int S){
    map<vector<int>,int>mp;
    vector<int>cnt(9,0),hash(9,0);
    mp[hash]=a[1].pos;
    int ret=-1,first=0;
    for(int i=1;i<=n;i++){
        cnt[a[i].col]++;
        if(!S>>(a[i].col-1)&1){
            hash[a[i].col]++;
        }
        else{
            if(!first){
                first=a[i].col;
            }
            for(int i=1;i<=8;i++){
                if(S>>(i-1)&1){
                    hash[i]=cnt[first]-cnt[i];
                }
            }
        }
        vector<int>need(9,0);
        for(int i=1;i<=8;i++){
            if(S>>(i-1)&1){
                if(!cnt[i]){
                    need[i]=-1;
                }
                else{
                    need[i]=cnt[first]-cnt[i];
                }
            }
            else{
                need[i]=cnt[i];
            }
        }
        if(mp.find(need)!=mp.end()){
            ret=max(ret,a[i].pos-mp[need]);
        }
        if(mp.find(hash)==mp.end()){
            mp[hash]=a[i+1].pos;    
        }
    }
    return ret;
}
int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        cin>>a[i].pos>>a[i].col;
    }
    sort(a+1,a+n+1);
    for(int i=0;i<(1<<8);i++){
        if(count(i)>=m){
            ans=max(ans,calc(i));
        }
    }
    cout<<ans;
}