Submission #957824

#	Time	Username	Problem	Language	Result	Execution time	Memory
957824		hirayuu_oj	Handcrafted Gift (IOI20_gift)	C++17	15 / 100	133 ms	20888 KiB

gift

#include "gift.h"
#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0; i<(n); i++)
#define rep2(i,a,b) for(int i=(a); i<(b); i++)
#define all(x) x.begin(),x.end()
using ll=long long;

char change(char c){
    if(c=='R')return 'B';
    return 'R';
}
int construct(int n, int r, std::vector<int> a, std::vector<int> b, std::vector<int> x) {
    string s(n,'-');
    vector<pair<int,int>> mono;
    rep(i,r){
        if(x[i]==1){
            mono.push_back({a[i],b[i]+1});
        }
    }
    sort(all(mono));
    int lf=0,ri=0;
    char fi='R';
    for(auto &[sl,sr]:mono){
        if(sl<ri){
            ri=sr;
        }
        else{
            rep2(i,lf,ri){
                s[i]=fi;
            }
            if((sl-ri)%2==0){
                fi=change(fi);
            }
            lf=sl;
            ri=sr;
        }
    }
    rep2(i,lf,ri){
        s[i]=fi;
    }
    char now='R';
    rep(i,n){
        if(s[i]=='-'){
            now=change(now);
            s[i]=now;
        }
        else{
            now=s[i];
        }
    }
    vector<ll> cumr(n+1,0);
    vector<ll> cumb(n+1,0);
    rep(i,n){
        cumr[i+1]=cumr[i];
        cumb[i+1]=cumb[i];
        if(s[i]=='R'){
            cumr[i+1]++;
        }
        else{
            cumb[i+1]++;
        }
    }
    rep(i,r){
        int red=cumr[b[i]+1]-cumr[a[i]];
        int blue=cumb[b[i]+1]-cumb[a[i]];
        int col=0;
        if(red!=0)col++;
        if(blue!=0)col++;
        if(x[i]!=col){
            return 0;
        }
    }
    craft(s);
    return 1;
}

• Subtask 1: 0 / 10
• Subtask 2: 15 / 15
• Subtask 3: 0 / 20
• Subtask 4: 0 / 25
• Subtask 5: 0 / 30