Submission #3644396

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define all(x) (x).begin(),(x).end()
typedef pair<int,int> P;

struct Trie{
    int cnt;
    int to[2];
    int id;
    Trie(){
    }
};

int sz=1;
int qsz=0;
queue<int> que[100005];
Trie t[1<<22];
int a[100005];
int sum[100005];

void init(){
    for(int i=0;i<(1<<22);i++){
        t[i].cnt=0;
        t[i].to[0]=-1;
        t[i].to[1]=-1;
        t[i].id=-1;
    }
}

void add(int v,int id){
    int cur=0;
    for(int i=20;i>=0;i--){
        t[cur].cnt++;
        int b=(v>>i)&1;
       // printf("add %d %d %d\n",v,i,b);
        if(t[cur].to[b]==-1){
            t[cur].to[b]=sz++;
        }
        cur=t[cur].to[b];
    }
    t[cur].cnt++;
    if(t[cur].id==-1)t[cur].id=qsz++;
    que[t[cur].id].push(id);
}

void del(int v){
    int cur=0;
    for(int i=20;i>=0;i--){
        t[cur].cnt--;
        int b=(v>>i)&1;
        if(t[cur].to[b]==-1){
            t[cur].to[b]=sz++;
        }
        cur=t[cur].to[b];
    }
    t[cur].cnt--;
    que[t[cur].id].pop();
}

P query(int v){
    int cur=0;
    P ans=P(0,-1);
    for(int i=20;i>=0;i--){
        int b=1-((v>>i)&1);
        int nxt=t[cur].to[b];
       // printf("%d %d %d\n",i,b,nxt);
        if(nxt==-1 || t[nxt].cnt==0){
            nxt=t[cur].to[1-b];
        }else{
            ans.first+=(1<<i);
        }
        cur=nxt;
    }
    ans.second=que[t[cur].id].front();
    return ans;
}

int main(){
    int n;
    scanf("%d",&n);
    init();
    for(int i=0;i<n;i++){
        scanf("%d",&a[i]);
        sum[i+1]+=sum[i];
        sum[i+1]^=a[i];
        add(sum[i+1],i+1);
    }
    int ans=-1;
    P p=P(0,0);
    for(int i=0;i<n;i++){
        P q=query(sum[i]);
        if(q.first>ans){
            ans=q.first;
            p=P(i+1,q.second);
        }
        del(sum[i+1]);
    }
    printf("%d %d %d\n",ans,p.first,p.second);
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:82:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
                   ^
./Main.cpp:85:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&a[i]);
                          ^

Judge Result