C++(clang++ 11.0.1) 解法, 执行用时: 50ms, 内存消耗: 1984K, 提交时间: 2023-07-12 09:00:21

#include<bits/stdc++.h>
using namespace std;
const int N=1e5+10;
typedef long long ll;
typedef struct lalala
{
    int id,x;
}vt;
vt v[N];
bool cmp(lalala a,lalala b)
{
    return a.id<b.id;
}
ll b[N];
ll solve(int l,int r)
{
    ll ans=0,res=0;
    for(int i=l;i<=r;++i)
    res^=v[i].x,b[i]=res,ans+=res;
    if(v[l].id==1) return ans;
    ans=0;
    for(int k=0;k<=30;++k)
    {
        ll c1=1<<k,c2=0;
        for(int i=l;i<=r;++i)
        {
            if((b[i]>>k)&1) c2+=1<<k;
            else c1+=1<<k;
        }
        ans+=min(c1,c2);
    }
    return ans;
}
int main()
{
    ios::sync_with_stdio(false);
   int n,m;
    cin>>n>>m;int a,b;
    for(int i=1;i<=m;++i)
    {
        cin>>a>>b;
        v[i]={a,b};
    }
    sort(v+1,v+m+1,cmp);
    int j=1;
    ll ans=0;
    for(int i=1;i<=m;i=j)
    {
        while(j<=m&&v[j].id+1==v[j+1].id) j++;
        ans+=solve(i,j);
        ++j;
    }
    cout<<ans;
    return 0;
}